0 00:00:07,829 --> 00:00:12,266 NARRATOR: Our planet is full of incredible natural wonders. 1 00:00:12,309 --> 00:00:13,583 Look at that! 2 00:00:15,829 --> 00:00:17,103 Whoo! 3 00:00:17,149 --> 00:00:19,583 It has immense power... 4 00:00:22,029 --> 00:00:27,183 ...and yet, that's rarely mentioned in our history books. 5 00:00:28,709 --> 00:00:31,826 I'm here to change that. 6 00:00:34,349 --> 00:00:38,547 I'm looking at four ways the power of the planet 7 00:00:38,589 --> 00:00:40,466 has shaped our history. 8 00:00:48,269 --> 00:00:52,228 The power of fire... 9 00:00:52,269 --> 00:00:53,941 Oh... 10 00:00:53,989 --> 00:00:57,504 ...that fuelled great technological breakthroughs. 11 00:00:58,549 --> 00:00:59,538 Wind... 12 00:00:59,589 --> 00:01:01,102 (CHUCKLES) 13 00:01:03,029 --> 00:01:06,624 ...that has influenced the rise and fall of empires. 14 00:01:09,669 --> 00:01:11,148 Water. .. 15 00:01:13,389 --> 00:01:18,941 ...our struggle to control it has directed human progress. 16 00:01:21,189 --> 00:01:26,707 But this week, I'm looking inside the Earth itself. 17 00:01:28,469 --> 00:01:32,781 It's an unknown world, hot and extreme. 18 00:01:34,829 --> 00:01:37,343 (CHUCKLES) 19 00:01:39,749 --> 00:01:44,061 It's provided the raw materials for our conquest of the planet, 20 00:01:44,109 --> 00:01:45,588 but at a price. 21 00:01:49,469 --> 00:01:55,101 This is the great untold story of human history. 22 00:02:09,749 --> 00:02:12,309 Hidden unseen within the Earth, 23 00:02:12,349 --> 00:02:14,624 extraordinary geological forces are at work. 24 00:02:14,669 --> 00:02:18,264 Hi. Gracias. 25 00:02:18,309 --> 00:02:20,345 Forces that have shaped our history. 26 00:02:23,509 --> 00:02:26,307 To really understand and appreciate them, 27 00:02:26,349 --> 00:02:28,419 I've got to go deep into the Earth itself. 28 00:02:34,189 --> 00:02:38,580 This is the Naica mine in northern Mexico - 29 00:02:38,629 --> 00:02:41,189 the starting point for a journey to one of the most 30 00:02:41,229 --> 00:02:47,145 spectacular and extreme places on or in the planet. 31 00:02:47,189 --> 00:02:50,340 I'm really starting to feel it now. 32 00:02:50,389 --> 00:02:54,985 I'm getting hotter and hotter, the deeper in I go. 33 00:02:55,029 --> 00:02:58,578 This heat is just a taste of what lies ahead. 34 00:03:04,469 --> 00:03:08,701 Finally, I arrive at what they call ''Base Camp''. 35 00:03:08,749 --> 00:03:13,948 You know, where I'm heading is just so extreme, so oppressive 36 00:03:13,989 --> 00:03:20,542 that I'm going to need all of these people, all of these control systems 37 00:03:20,589 --> 00:03:24,104 and all of this kit over here just to get there. 38 00:03:24,149 --> 00:03:26,265 It's going to be like visiting another planet. 39 00:03:29,349 --> 00:03:33,137 Beyond here is a chamber that reveals the power of the inner Earth 40 00:03:33,189 --> 00:03:35,419 to influence human affairs. 41 00:03:35,469 --> 00:03:37,221 But to get there, 42 00:03:37,269 --> 00:03:40,386 they've had to develop some pretty esoteric equipment. 43 00:03:42,429 --> 00:03:44,897 Get this. 44 00:03:44,949 --> 00:03:47,702 It's like a chain mail of ice cubes. 45 00:03:47,749 --> 00:03:49,182 It's heavy, isn't it? 46 00:03:49,229 --> 00:03:52,665 The special refrigerated suit will keep me cool. 47 00:03:52,709 --> 00:03:53,698 What a palaver! 48 00:03:55,909 --> 00:03:58,298 - This brings down my core temperature? - Yes. 49 00:03:58,349 --> 00:04:00,783 Oh, feels very cold suddenly. 50 00:04:00,829 --> 00:04:02,945 (LAUGHS) That's very odd. 51 00:04:04,429 --> 00:04:07,660 But it's not the heat alone that's potentially lethal. 52 00:04:10,949 --> 00:04:13,179 This is what? This is the oxygen? 53 00:04:13,229 --> 00:04:16,938 MAN: Yes, it's fresh air. 54 00:04:16,989 --> 00:04:19,503 - It's fresh air. - Yes. You'll need it. 55 00:04:19,549 --> 00:04:23,428 The heat is combined with nearly 1 oo% humidity. 56 00:04:23,469 --> 00:04:25,380 If I breathed that combination, 57 00:04:25,429 --> 00:04:28,421 moisture would begin to condense inside my lungs. 58 00:04:28,469 --> 00:04:32,621 After about ten minutes, I'd start to suffocate. 59 00:04:32,669 --> 00:04:35,786 - You're ready. - I'm ready? I don't feel ready. 60 00:04:35,829 --> 00:04:38,297 OK. 61 00:04:42,029 --> 00:04:44,623 Without this suit, I could die. 62 00:04:44,669 --> 00:04:46,307 It seems a lot of effort, 63 00:04:46,349 --> 00:04:51,298 but inside there is one of the geological wonders of the world. 64 00:04:57,109 --> 00:04:59,259 (BREATHES HEAVILY) 65 00:05:11,749 --> 00:05:14,547 (WONDROUS MUSIC) 66 00:05:29,069 --> 00:05:32,061 That is unbelievable. 67 00:05:41,429 --> 00:05:43,863 (LAUGHS) This is just mad! 68 00:05:45,469 --> 00:05:47,346 Absolutely gorgeous, isn't it? 69 00:05:50,349 --> 00:05:53,147 This is la Cueva de los Cristales - 70 00:05:53,189 --> 00:05:56,659 for my money, the most spectacular cave of crystals 71 00:05:56,709 --> 00:05:58,665 discovered anywhere in the world. 72 00:06:00,109 --> 00:06:02,703 (CHUCKLES) 73 00:06:02,749 --> 00:06:05,741 You know, I've travelled around the world 74 00:06:05,789 --> 00:06:08,019 to see some of the most amazing geology, 75 00:06:08,069 --> 00:06:11,857 but this place - this place just tops it all. 76 00:06:11,909 --> 00:06:14,707 Look at it. 77 00:06:16,229 --> 00:06:18,823 It really looks perfect. 78 00:06:20,709 --> 00:06:23,542 You can see through them, they're so translucent. 79 00:06:23,589 --> 00:06:25,068 And there's different types. 80 00:06:25,109 --> 00:06:27,862 You can see these ones that are like roses building up 81 00:06:27,909 --> 00:06:30,901 and then these columns, these pillars - 82 00:06:30,949 --> 00:06:32,940 absolutely magnificent. 83 00:06:42,389 --> 00:06:46,940 Until recently, no-one knew this chamber existed. 84 00:06:46,989 --> 00:06:51,107 It was uncovered when miners broke through by chance. 85 00:07:00,549 --> 00:07:03,461 (LAUGHS) You know, these extraordinary crystals 86 00:07:03,509 --> 00:07:07,787 are made up almost entirely of a pretty ordinary mineral - gypsum - 87 00:07:07,829 --> 00:07:12,107 but it's the sheer scale of them that astounds you. 88 00:07:19,309 --> 00:07:22,665 This strange world is shaped by forces 89 00:07:22,709 --> 00:07:25,940 that have had a profound impact on human civilisation. 90 00:07:32,989 --> 00:07:36,061 (PANTS) 91 00:07:39,669 --> 00:07:42,547 Oh, this heat... This heat's just too much. 92 00:07:42,589 --> 00:07:44,659 It's unbearable. 93 00:07:44,709 --> 00:07:47,746 But, oh, hey, the heat - that's what it's all about. 94 00:07:47,789 --> 00:07:49,222 That's the whole point. 95 00:07:49,269 --> 00:07:53,387 It's this cauldron that's the reason that these crystals are here. 96 00:07:57,709 --> 00:08:02,658 It's so hot because only about 5km below the cavern... 97 00:08:03,709 --> 00:08:09,022 ...is an area of the Earth's crust that is super-heated molten rock. 98 00:08:14,429 --> 00:08:19,628 This heats water, which dissolves minerals from the surrounding rock. 99 00:08:19,669 --> 00:08:24,185 Phenomenal pressure forces this mineral-rich water 100 00:08:24,229 --> 00:08:28,745 up through cracks in the rock and filled this giant cavern. 101 00:08:30,109 --> 00:08:32,259 Here, the conditions were perfect 102 00:08:32,309 --> 00:08:35,699 for the minerals to slowly crystallise back out of the water. 103 00:08:35,749 --> 00:08:40,459 The cave lay undisturbed for over half a million years, 104 00:08:40,509 --> 00:08:45,788 so the gypsum crystals just kept growing 105 00:08:45,829 --> 00:08:49,663 until the miners broke through and the cave was drained. 106 00:08:52,189 --> 00:08:56,944 But the hot inner Earth has done far more than create these crystals. 107 00:08:58,669 --> 00:09:03,299 This incredible hot world hidden just beneath the surface 108 00:09:03,349 --> 00:09:06,819 is a driving force for powerful geological events 109 00:09:06,869 --> 00:09:10,259 that have shaped the fate of peoples throughout history. 110 00:09:17,469 --> 00:09:22,463 This is the Timna Valley in Israel's Negev Desert. 111 00:09:23,789 --> 00:09:26,622 Today it's pretty well deserted. 112 00:09:26,669 --> 00:09:30,025 But over 6,ooo years ago, 113 00:09:30,069 --> 00:09:31,627 this place witnessed 114 00:09:31,669 --> 00:09:34,627 one of the world's first great scientific breakthroughs. 115 00:09:42,349 --> 00:09:43,828 Up until this point, 116 00:09:43,869 --> 00:09:47,100 humans had made all their tools from stuff just lying around - 117 00:09:47,149 --> 00:09:50,027 stone, wood, bone, 118 00:09:50,069 --> 00:09:52,663 anything, really, that they could get their hands on. 119 00:09:54,309 --> 00:09:57,745 But then, between 6,ooo-7,ooo years ago, 120 00:09:57,789 --> 00:10:02,817 our ancestors made an extraordinary imaginative leap. 121 00:10:02,869 --> 00:10:07,147 They realised that the rock here contained a secret. 122 00:10:09,589 --> 00:10:13,343 These green bands are called malachite. 123 00:10:13,389 --> 00:10:15,664 And it was these malachite seams 124 00:10:15,709 --> 00:10:17,586 that around 6,5OO years ago 125 00:10:17,629 --> 00:10:21,099 were at the centre of that incredible leap of human ingenuity. 126 00:10:24,869 --> 00:10:28,384 Like the gypsum inside the crystal cave, 127 00:10:28,429 --> 00:10:30,147 these bands of malachite 128 00:10:30,189 --> 00:10:33,943 formed when hot fluids rose from deep inside the planet 129 00:10:33,989 --> 00:10:36,503 and leaked into these rocks. 130 00:10:41,149 --> 00:10:42,787 But unlike gypsum, 131 00:10:42,829 --> 00:10:45,138 when malachite is heated up... 132 00:10:50,269 --> 00:10:52,146 ...it does something special. 133 00:10:53,789 --> 00:10:57,941 It releases a metal. 134 00:10:58,949 --> 00:11:00,860 Copper. 135 00:11:16,029 --> 00:11:17,508 You know, in its day, 136 00:11:17,549 --> 00:11:21,508 this copper axe head would have been the pinnacle of technology. 137 00:11:21,549 --> 00:11:23,301 For a start, it's weighty. 138 00:11:23,349 --> 00:11:27,547 If you hit something or someone with this, it would leave a dent. 139 00:11:27,589 --> 00:11:30,979 For another thing, it's hard enough to take an edge. 140 00:11:31,029 --> 00:11:33,987 And if it gets blunt, you just sharpen it up. 141 00:11:36,069 --> 00:11:41,746 You can still see evidence of the ancient smelting pits at Timna. 142 00:11:44,589 --> 00:11:49,788 But the copperworkers left behind a more striking memorial to their work. 143 00:11:55,709 --> 00:12:00,100 A network of hundreds of tunnels, all carved by hand. 144 00:12:03,109 --> 00:12:08,388 This was the first large-scale mining anywhere on the planet. 145 00:12:09,669 --> 00:12:11,785 Those early copper miners 146 00:12:11,829 --> 00:12:16,380 would have squeezed through these narrow shafts on all fours, 147 00:12:16,429 --> 00:12:19,466 smashing their way through the rock 148 00:12:19,509 --> 00:12:24,060 and hauling their pails of copper-laced ore back to the surface. 149 00:12:34,109 --> 00:12:35,588 You know, the copper revolution 150 00:12:35,629 --> 00:12:37,620 changed our relationship with the planet 151 00:12:37,669 --> 00:12:39,739 in a really profound way. 152 00:12:39,789 --> 00:12:41,381 For the first time, 153 00:12:41,429 --> 00:12:43,818 we were transforming what the Earth offered us 154 00:12:43,869 --> 00:12:47,544 and in the process creating entirely new resources. 155 00:12:47,589 --> 00:12:50,899 And copper was just the start of things to come. 156 00:12:56,549 --> 00:13:00,337 About 5,ooo years ago, tin was added to copper 157 00:13:00,389 --> 00:13:05,179 to form a new, more durable metal alloy - bronze. 158 00:13:11,549 --> 00:13:15,622 By 3,ooo years ago, refinements to the smelting process 159 00:13:15,669 --> 00:13:19,344 meant iron could be smelted out of rock. 160 00:13:22,909 --> 00:13:27,664 Metal tools became the foundation for human civilisation. 161 00:13:33,029 --> 00:13:38,547 So it's clear we owe a huge debt to those first copper miners at Timna. 162 00:13:40,989 --> 00:13:44,538 But we also owe a debt to the deep Earth. 163 00:13:47,509 --> 00:13:52,583 The key to Timna's role in early history is its location. 164 00:13:59,549 --> 00:14:04,065 The Earth's crust is divided into huge pieces called plates. 165 00:14:04,109 --> 00:14:07,146 Where they meet are cracks known as fault lines. 166 00:14:10,389 --> 00:14:13,347 Timna is next to the Dead Sea fault 167 00:14:13,389 --> 00:14:15,857 which separates Africa from Arabia. 168 00:14:17,909 --> 00:14:22,744 But this fault also connects Timna to the deep, hot interior of the Earth. 169 00:14:25,229 --> 00:14:27,265 It's this hot interior 170 00:14:27,309 --> 00:14:29,027 that is ultimately the source 171 00:14:29,069 --> 00:14:32,300 of all the metals that have so radically changed our history. 172 00:14:35,149 --> 00:14:38,664 Fault lines allow them to rise to the surface... 173 00:14:44,109 --> 00:14:48,182 ...just as they did at the crystal cave in Mexico. 174 00:14:57,189 --> 00:15:00,226 But fault lines began affecting human history 175 00:15:00,269 --> 00:15:03,102 even before the discovery of metals. 176 00:15:03,149 --> 00:15:08,018 In fact, we've been strangely drawn to these boundary zones 177 00:15:08,069 --> 00:15:10,458 ever since the dawn of civilisation. 178 00:15:13,069 --> 00:15:14,548 And you can see why 179 00:15:14,589 --> 00:15:18,059 in the barren wilderness of the Lut Desert in Iran. 180 00:15:20,709 --> 00:15:26,261 The landscape is covered in hundreds of holes arranged in rows. 181 00:15:26,309 --> 00:15:28,106 These holes in the desert 182 00:15:28,149 --> 00:15:32,028 can help explain our ancient attraction to fault lines. 183 00:15:35,669 --> 00:15:39,947 But that involves me going down one - 184 00:15:39,989 --> 00:15:43,140 something the locals seem a little bemused by. 185 00:15:45,229 --> 00:15:46,503 Hi. 186 00:15:47,949 --> 00:15:49,507 So this is it? 187 00:15:49,549 --> 00:15:51,028 (SPEAKS LOCAL LANGUAGE) 188 00:15:53,909 --> 00:15:55,547 That's tiny! 189 00:15:55,589 --> 00:15:58,422 I don't think I'll really fit. 190 00:15:58,469 --> 00:16:01,347 How deep is it? 191 00:16:04,709 --> 00:16:06,461 (THUD!) 192 00:16:08,629 --> 00:16:12,827 God! Apparently it's 5O metres. 193 00:16:12,869 --> 00:16:15,667 That's over 1 5O feet. 194 00:16:15,709 --> 00:16:17,825 OK, I guess we do it, huh? 195 00:16:17,869 --> 00:16:19,939 So we go down? 196 00:16:22,589 --> 00:16:25,786 And if this deep, dark hole wasn't scary enough, 197 00:16:25,829 --> 00:16:30,186 the method for going down is unconventional at best. 198 00:16:30,229 --> 00:16:32,697 So we take this, like a pulley? 199 00:16:34,469 --> 00:16:36,221 And this goes over the top, I guess. 200 00:16:37,509 --> 00:16:39,022 So do I go on this? 201 00:16:41,029 --> 00:16:44,385 You can't buy those, I bet you! 202 00:16:44,429 --> 00:16:48,263 I've never gone on a rope with a metal tripod pulled by a tractor before. 203 00:16:48,309 --> 00:16:49,344 So... 204 00:16:50,349 --> 00:16:53,261 (TRACTOR ENGINE REVS) 205 00:16:56,429 --> 00:16:59,501 Well, I think we should just do this before I change my mind. 206 00:16:59,549 --> 00:17:01,904 OK. What could possibly go wrong now? 207 00:17:06,829 --> 00:17:10,265 Blooming heck. It really is deep. 208 00:17:26,829 --> 00:17:29,218 Oh, this isn't natural. 209 00:17:29,269 --> 00:17:32,341 I'm getting lowered down into the bowels of the Earth here. 210 00:17:35,629 --> 00:17:38,223 I wasn't sure if I was claustrophobic 211 00:17:38,269 --> 00:17:41,022 but now I realise I think I am. 212 00:17:42,269 --> 00:17:44,225 (GASPS) It's so far up! 213 00:17:45,749 --> 00:17:47,421 Look at that. 214 00:17:47,469 --> 00:17:49,380 Oh, dear. I don't want to do this too many times. 215 00:17:52,709 --> 00:17:53,903 (EXHALES) 216 00:17:53,949 --> 00:17:56,144 (METAL TAPS) 217 00:17:57,229 --> 00:17:59,504 For over 2,ooo years, 218 00:17:59,549 --> 00:18:03,906 local people have been digging shafts like this - by hand. 219 00:18:03,949 --> 00:18:07,783 And I get the sense I'm about to find out why. 220 00:18:07,829 --> 00:18:09,308 (SIGHS) 221 00:18:09,349 --> 00:18:11,101 All right, here we go. 222 00:18:11,149 --> 00:18:12,628 Hey hey! 223 00:18:12,669 --> 00:18:14,978 Ooh! Oof! 224 00:18:15,029 --> 00:18:16,826 (WATER SPLASHES) 225 00:18:16,869 --> 00:18:18,825 I misjudged it. 226 00:18:18,869 --> 00:18:21,622 Look at this! 227 00:18:21,669 --> 00:18:23,739 This is the answer. 228 00:18:23,789 --> 00:18:27,099 The essential ingredient of every civilisation on Earth. 229 00:18:28,109 --> 00:18:30,100 Cold, fresh drinking water. 230 00:18:30,149 --> 00:18:34,028 This is what made this remote corner of the Lut Desert 231 00:18:34,069 --> 00:18:38,062 one of the few places in the region that could sustain towns and cities. 232 00:18:38,109 --> 00:18:39,940 And I'll tell you... 233 00:18:40,949 --> 00:18:44,862 ...after a trip like that, this is so nice to have. 234 00:18:44,909 --> 00:18:46,422 (SIGHS) 235 00:18:46,469 --> 00:18:50,587 Right. I'm off to explore a bit. 236 00:18:52,589 --> 00:18:55,945 I want to find where the water's coming from. 237 00:19:01,829 --> 00:19:06,539 This tunnel leading off the shaft is called a qanat. 238 00:19:08,549 --> 00:19:11,268 It's one of many in this region, 239 00:19:11,309 --> 00:19:13,186 hacked out of solid rock 240 00:19:13,229 --> 00:19:17,188 to capture ground water that's stored deep below the desert. 241 00:19:18,269 --> 00:19:22,547 I feel as if I'm in an underground rain shower. 242 00:19:30,189 --> 00:19:34,023 I've travelled about, I don't know, a couple of hundred metres now 243 00:19:34,069 --> 00:19:36,139 and it seems to be getting smaller and smaller. 244 00:19:37,469 --> 00:19:39,187 (GROANS) 245 00:19:39,229 --> 00:19:40,947 It's a bit narrow here. 246 00:19:45,229 --> 00:19:46,787 Well, this is it. 247 00:19:46,829 --> 00:19:49,218 This is the source of all this water. 248 00:19:49,269 --> 00:19:51,464 It's just pouring in from here. 249 00:19:54,509 --> 00:19:57,899 Underground water exists beneath most deserts. 250 00:19:57,949 --> 00:19:59,587 But it's usually so far down, 251 00:19:59,629 --> 00:20:02,905 there's no practical way of getting at it. 252 00:20:02,949 --> 00:20:05,782 The difference is, here there's a fault line. 253 00:20:09,309 --> 00:20:11,300 The fault is full of thick clay 254 00:20:11,349 --> 00:20:14,147 produced by the grinding of the surrounding rocks 255 00:20:14,189 --> 00:20:16,145 as they rub along the fault line. 256 00:20:16,189 --> 00:20:21,866 This forms a clay dam which water can't penetrate. 257 00:20:21,909 --> 00:20:25,140 Water flowing down from the mountains 258 00:20:25,189 --> 00:20:26,827 pools against the dam, 259 00:20:26,869 --> 00:20:29,667 creating an underground reservoir 260 00:20:29,709 --> 00:20:34,419 through which a qanat is dug to channel the water. 261 00:20:34,469 --> 00:20:37,620 Gravity does the rest. 262 00:20:39,629 --> 00:20:43,941 So originally the water would've been banked up against this fault line, 263 00:20:43,989 --> 00:20:47,345 unable to penetrate through the clay-rich barrier. 264 00:20:47,389 --> 00:20:51,462 But what the locals did was to cut a qanat across the fault line, 265 00:20:51,509 --> 00:20:54,228 breaching the barrier and releasing the water. 266 00:20:54,269 --> 00:20:57,067 It was a simple but brilliant piece of engineering. 267 00:20:58,269 --> 00:20:59,702 OK. 268 00:21:10,909 --> 00:21:16,506 Qanats were an ingenious early example of a mains water supply. 269 00:21:16,549 --> 00:21:19,063 The shaft is simply a way 270 00:21:19,109 --> 00:21:21,907 to get access to the tunnel carrying the water, so it can be repaired. 271 00:21:23,869 --> 00:21:27,100 Today, the qanats still carry water from underneath the Lut Desert 272 00:21:27,149 --> 00:21:29,583 into the nearby city of Bam, 273 00:21:29,629 --> 00:21:35,022 as well as irrigating the date orchards for which this area is famous. 274 00:21:48,669 --> 00:21:51,058 Oh! Oh, it's so good to see blue sky. 275 00:21:51,109 --> 00:21:52,747 Oh! 276 00:21:52,789 --> 00:21:54,507 Yeah, thank you. 277 00:21:54,549 --> 00:21:57,859 But this place isn't a one-off. 278 00:21:57,909 --> 00:22:01,538 In fact, if you look back at the ancient world, 279 00:22:01,589 --> 00:22:04,547 you see a strong link between fault lines, 280 00:22:04,589 --> 00:22:10,425 water and the growth of some of the first cities. 281 00:22:12,349 --> 00:22:15,978 More than 2,ooo years ago, Petra in Jordan 282 00:22:16,029 --> 00:22:19,180 was the most important trade hub in the Middle East. 283 00:22:25,549 --> 00:22:29,701 It was built along a branch of the Dead Sea fault 284 00:22:29,749 --> 00:22:34,425 and was entirely dependent on natural springs 285 00:22:34,469 --> 00:22:38,348 which rose along the fault and fed its irrigation system. 286 00:22:48,229 --> 00:22:53,781 Nearby is Jericho, said to be the oldest city in the world. 287 00:22:53,829 --> 00:22:57,219 It was first settled 1 o,ooo years ago 288 00:22:57,269 --> 00:22:59,942 because deep ground water rose along fault lines 289 00:22:59,989 --> 00:23:04,107 to create fertile pastures in the desert. 290 00:23:09,589 --> 00:23:13,821 More unusual is the ancient Roman city of Hierapolis. 291 00:23:13,869 --> 00:23:17,418 It was built next to these terraces of white rock. 292 00:23:24,989 --> 00:23:27,901 Here, it wasn't just water that was important - 293 00:23:27,949 --> 00:23:33,660 minerals carried in the water were thought to have revitalising powers. 294 00:23:34,949 --> 00:23:38,737 So Hierapolis became an important healing centre 295 00:23:38,789 --> 00:23:40,780 in the Roman Empire. 296 00:23:49,629 --> 00:23:53,178 Whether it was minerals, metals or water, 297 00:23:53,229 --> 00:23:57,222 ancient civilisations were repeatedly drawn to the resources 298 00:23:57,269 --> 00:24:00,864 that fault lines brought up from the deep Earth. 299 00:24:04,949 --> 00:24:09,704 It's a connection which lead 1 1 of the 1 3 most important civilisations 300 00:24:09,749 --> 00:24:11,307 of the ancient world 301 00:24:11,349 --> 00:24:15,501 unknowingly to build their cities close to a plate boundary. 302 00:24:21,629 --> 00:24:24,063 As the earliest civilisations developed, 303 00:24:24,109 --> 00:24:27,340 so the relationship between fault lines and human history 304 00:24:27,389 --> 00:24:29,539 became more sophisticated. 305 00:24:29,589 --> 00:24:31,580 They even played a role 306 00:24:31,629 --> 00:24:35,747 in the establishment of the most advanced early civilisation of all. 307 00:24:38,189 --> 00:24:40,749 4,ooo years ago, in the Bronze Age, 308 00:24:40,789 --> 00:24:43,542 the island of Crete was home to the Minoans. 309 00:24:58,069 --> 00:25:01,459 Their showpiece was the palace of Knossos. 310 00:25:10,149 --> 00:25:13,664 You can see by the sheer scale and sophistication of Knossos 311 00:25:13,709 --> 00:25:16,985 that the Minoans weren't just another early civilisation. 312 00:25:17,029 --> 00:25:20,942 This, in a way, was the beginning of modern society. 313 00:25:20,989 --> 00:25:22,468 Certainly, this was a place 314 00:25:22,509 --> 00:25:25,819 that you and I would have felt reasonably at home. 315 00:25:32,109 --> 00:25:35,499 There was running water, a sewage system 316 00:25:35,549 --> 00:25:38,109 and large stores of food and wine. 317 00:25:45,469 --> 00:25:49,860 It all allowed the Minoans to create a new kind of society. 318 00:25:54,389 --> 00:25:57,506 For me, all this is a moment in history 319 00:25:57,549 --> 00:26:00,109 that is much under appreciated. 320 00:26:00,149 --> 00:26:03,858 What the Minoans represent is a great pivotal point 321 00:26:03,909 --> 00:26:09,222 when life switched from being dictated by the grim realities of survival 322 00:26:09,269 --> 00:26:11,942 into something that we could actually enjoy. 323 00:26:11,989 --> 00:26:15,982 What the Minoans invented was the day off. 324 00:26:18,909 --> 00:26:23,027 And the Minoans took their pioneering responsibilities 325 00:26:23,069 --> 00:26:25,105 in this area very seriously. 326 00:26:26,989 --> 00:26:28,820 Now, this may look like a car park, 327 00:26:28,869 --> 00:26:31,508 but, really, this is where the paraphernalia 328 00:26:31,549 --> 00:26:34,222 of the Minoan leisure society really took off 329 00:26:34,269 --> 00:26:38,182 because this is one of world's first sports stadiums. 330 00:26:46,069 --> 00:26:49,345 In its day, 5OO spectators would cram in here 331 00:26:49,389 --> 00:26:51,380 to watch boxing, wrestling, 332 00:26:51,429 --> 00:26:55,217 and the Minoans' most peculiar sport, bull-leaping. 333 00:26:55,269 --> 00:26:59,342 The basic idea was that you wait for a massive bull to run at you, 334 00:26:59,389 --> 00:27:00,822 then at the crucial moment, 335 00:27:00,869 --> 00:27:04,020 you grab hold of the horns and flip yourself over the top. 336 00:27:06,189 --> 00:27:08,145 How do you practise that? 337 00:27:13,709 --> 00:27:16,826 No-one knows why the Minoans leapt over bulls, 338 00:27:16,869 --> 00:27:20,544 but this bizarre sport was a forerunner to bull-fighting. 339 00:27:26,309 --> 00:27:30,825 But the real legacy of the Minoans was how they made their wealth. 340 00:27:34,389 --> 00:27:36,141 This was the Bronze Age. 341 00:27:38,909 --> 00:27:42,618 To make bronze, you need two metals - copper and tin. 342 00:27:45,949 --> 00:27:48,827 The problem was finding them. 343 00:27:54,909 --> 00:27:59,141 For the Minoans, copper was relatively near at hand in Cyprus, 344 00:27:59,189 --> 00:28:01,180 thanks to the fault line beneath it. 345 00:28:08,069 --> 00:28:10,424 Tin was trickier. 346 00:28:10,469 --> 00:28:13,859 Inside the Earth's crust, only two parts per million are tin, 347 00:28:13,909 --> 00:28:16,139 so it's much rarer. 348 00:28:19,629 --> 00:28:22,268 The hunts for tin led to distant lands 349 00:28:22,309 --> 00:28:25,107 that were at the edge of the then-known world. 350 00:28:31,789 --> 00:28:34,178 One such place was so full of tin 351 00:28:34,229 --> 00:28:38,302 that it was called the Cassiterides - ''the tin islands''. 352 00:28:38,349 --> 00:28:40,101 Today... 353 00:28:42,069 --> 00:28:43,502 ...we know it as Britain. 354 00:28:50,589 --> 00:28:53,262 But the centres of Bronze-Age civilisation 355 00:28:53,309 --> 00:28:57,427 were in the Mediterranean, 3,oookm away. 356 00:28:57,469 --> 00:29:01,587 Tin was also found in other far-flung locations 357 00:29:01,629 --> 00:29:05,065 like Spain, Central Europe and even Iran... 358 00:29:06,669 --> 00:29:09,103 ...which meant tin had to be traded, 359 00:29:09,149 --> 00:29:12,778 and for this, Crete was perfectly positioned. 360 00:29:17,829 --> 00:29:19,706 The Minoans exploited their position 361 00:29:19,749 --> 00:29:23,378 at the crossroads of many different trading routes... 362 00:29:25,869 --> 00:29:30,420 ...to become the world's first maritime superpower. 363 00:29:32,869 --> 00:29:34,860 It may not seem like it today, 364 00:29:34,909 --> 00:29:39,107 but in Bronze Age times, this island was at the centre of the known world, 365 00:29:39,149 --> 00:29:40,662 with the mineral-rich heartlands 366 00:29:40,709 --> 00:29:44,588 of Europe, the Middle East and North Africa all around. 367 00:29:44,629 --> 00:29:48,417 For the Minoans, it wasn't so much about owning the raw materials 368 00:29:48,469 --> 00:29:51,984 as knowing what to do with them, how to put them together. 369 00:29:52,029 --> 00:29:56,147 They built an empire because they'd worked out how to exploit the geology 370 00:29:56,189 --> 00:29:58,657 that their neighbours had on their doorsteps. 371 00:30:05,829 --> 00:30:07,820 By the time of the Minoans, 372 00:30:07,869 --> 00:30:09,825 fault lines had been a crucial factor 373 00:30:09,869 --> 00:30:13,782 in the success of many early civilisations. 374 00:30:19,189 --> 00:30:22,625 But the Earth extracted a price for these riches. 375 00:30:24,269 --> 00:30:29,184 It was a price paid in full by the Minoans. 376 00:30:30,389 --> 00:30:33,984 At the heart of the story was a small archipelago 377 00:30:34,029 --> 00:30:36,384 1 ookm north of Crete. 378 00:30:40,389 --> 00:30:43,267 Today that island chain is known as Santorini, 379 00:30:43,309 --> 00:30:48,337 famous for its pretty white houses and rugged coastline. 380 00:30:58,789 --> 00:31:02,543 But at the time of the Minoans this was a busy port, 381 00:31:02,589 --> 00:31:05,308 the key to their trading empire. 382 00:31:07,429 --> 00:31:09,579 If Crete was the heart of the Minoan culture, 383 00:31:09,629 --> 00:31:12,348 then this place was its backbone, 384 00:31:12,389 --> 00:31:16,098 a centre of industry that helped fuel what was at the time 385 00:31:16,149 --> 00:31:19,346 the most advanced civilisation on the planet. 386 00:31:22,349 --> 00:31:25,546 But Santorini held a deadly secret. 387 00:31:28,029 --> 00:31:29,587 Unknown to the Minoans, 388 00:31:29,629 --> 00:31:33,463 it sat above one of the Earth's major plate boundaries. 389 00:31:37,389 --> 00:31:40,108 Santorini formed when the African plate 390 00:31:40,149 --> 00:31:43,107 started sliding below the European plate. 391 00:31:45,829 --> 00:31:49,265 As the African plate melted inside the deep Earth, 392 00:31:49,309 --> 00:31:52,028 molten rock rose back to the surface 393 00:31:52,069 --> 00:31:54,708 to create what is actually a volcano. 394 00:31:56,109 --> 00:31:59,784 (OMINOUS RUMBLING) 395 00:31:59,829 --> 00:32:02,582 Around 3,5OO years ago, 396 00:32:02,629 --> 00:32:06,065 this volcano did what volcanoes tend to do - 397 00:32:06,109 --> 00:32:07,622 it blew up. 398 00:32:17,549 --> 00:32:19,744 Unluckily for the Minoans, 399 00:32:19,789 --> 00:32:23,668 it was the biggest eruption of the last 1 o,ooo years. 400 00:32:25,349 --> 00:32:29,501 Today you can still trace why the eruption was so devastating 401 00:32:29,549 --> 00:32:31,301 in the cliffs around Santorini. 402 00:32:36,589 --> 00:32:42,107 This cliff is made entirely of ash and rock spat out by the volcano. 403 00:32:42,149 --> 00:32:45,107 It's got distinct layers to it, 404 00:32:45,149 --> 00:32:48,619 each of which are from different stages of the eruption. 405 00:32:48,669 --> 00:32:52,184 In other words, this rock face is a timeline of events. 406 00:32:55,589 --> 00:32:58,467 Climbing this cliff helps understand the disaster 407 00:32:58,509 --> 00:33:03,583 that was unlike anything anyone had ever seen before. 408 00:33:10,149 --> 00:33:12,219 This level here was the start of the eruption. 409 00:33:12,269 --> 00:33:16,228 I'm kind of standing on the Minoan land surface. 410 00:33:16,269 --> 00:33:17,782 And in the next five hours, 411 00:33:17,829 --> 00:33:21,504 the eruptions threw out an enormous mushroom cloud of debris. 412 00:33:26,029 --> 00:33:28,941 It just rained down ash after ash after ash. 413 00:33:34,269 --> 00:33:36,988 This stuff is just like a silica glass. 414 00:33:37,029 --> 00:33:40,339 It gets into your lungs and it just lacerates your lungs. 415 00:33:40,389 --> 00:33:41,822 You just choke on it. 416 00:33:57,349 --> 00:33:59,738 This innocent-looking gravel 417 00:33:59,789 --> 00:34:02,986 was from the second and most lethal stage of the eruption. 418 00:34:06,309 --> 00:34:10,985 Sea water invaded the volcano, and that mix of water with molten lava 419 00:34:11,029 --> 00:34:13,463 produced a series of incredibly violent eruptions 420 00:34:13,509 --> 00:34:17,468 that punched a jet of superheated gas and debris 421 00:34:17,509 --> 00:34:18,942 high into the atmosphere. 422 00:34:26,709 --> 00:34:29,621 As these clouds of hot gas and lava fell back to Earth, 423 00:34:29,669 --> 00:34:33,901 they engulfed the outer edges of the island. 424 00:34:33,949 --> 00:34:35,746 Ay! (GROANS) 425 00:34:38,749 --> 00:34:43,061 But, incredibly, the worst was still to come. 426 00:34:46,149 --> 00:34:49,824 Once the volcano had spewed out everything that was in its guts, 427 00:34:49,869 --> 00:34:52,827 the weight of it collapsed into the void below, 428 00:34:52,869 --> 00:34:55,099 producing the most enormous blast. 429 00:34:55,149 --> 00:34:58,744 And in the death throes of that final blast, 430 00:34:58,789 --> 00:35:01,667 there was one last catastrophic flourish. 431 00:35:07,349 --> 00:35:11,422 The centre of the volcano crashed into the sea. 432 00:35:18,509 --> 00:35:22,821 That sudden collapse created a gigantic tsunami... 433 00:35:24,509 --> 00:35:29,708 ...which quickly spread out across the Aegean towards Crete. 434 00:35:32,269 --> 00:35:35,261 (WAVE CRASHES) 435 00:35:36,989 --> 00:35:40,106 For a civilisation whose strength was in their navy, 436 00:35:40,149 --> 00:35:43,107 the tsunami would have been devastating. 437 00:35:48,149 --> 00:35:52,506 It's thought that as the tsunami swept through the Aegean, 438 00:35:52,549 --> 00:35:54,540 it engulfed the Minoan harbours, 439 00:35:54,589 --> 00:35:59,026 and any boats in them would have been smashed into matchsticks. 440 00:35:59,069 --> 00:36:01,902 So perhaps it's not that surprising that not a single boat 441 00:36:01,949 --> 00:36:03,507 from the vast Minoan fleet 442 00:36:03,549 --> 00:36:05,028 has ever been found. 443 00:36:13,309 --> 00:36:18,224 This was a catastrophe from which the Minoans would never recover. 444 00:36:27,909 --> 00:36:31,265 A long chalk-and-ash cloud and a giant tsunami 445 00:36:31,309 --> 00:36:35,222 meant that this maritime power was on its knees. 446 00:36:35,269 --> 00:36:38,944 With the fleet gone, their population decimated 447 00:36:38,989 --> 00:36:42,868 and their most strategic trading post obliterated, 448 00:36:42,909 --> 00:36:45,469 the Minoans went downhill fast. 449 00:36:45,509 --> 00:36:47,864 Within a century or so of the eruption, 450 00:36:47,909 --> 00:36:52,744 this once-great civilisation was finished. 451 00:36:57,349 --> 00:36:58,782 The eruption of Santorini 452 00:36:58,829 --> 00:37:01,343 was an extreme event. 453 00:37:01,389 --> 00:37:03,266 But ancient history is littered with 454 00:37:03,309 --> 00:37:07,666 tales of cities destroyed along plate boundaries. 455 00:37:13,589 --> 00:37:17,821 And it's not just volcanoes that do the damage. 456 00:37:17,869 --> 00:37:21,908 Fault lines are also home to another deadly force of nature. 457 00:37:28,149 --> 00:37:29,821 (RATTLING AND RUMBLING) 458 00:37:34,349 --> 00:37:35,782 Earthquakes. 459 00:37:42,709 --> 00:37:44,620 Over the past 1 o,ooo years, 460 00:37:44,669 --> 00:37:48,378 many cities first established to take advantage of fault lines 461 00:37:48,429 --> 00:37:50,226 have been flattened. 462 00:37:55,669 --> 00:37:58,741 Hierapolis, with its famous health spa, 463 00:37:58,789 --> 00:38:02,384 was destroyed by a giant earthquake in AD 6o. 464 00:38:07,349 --> 00:38:09,704 Jericho, the oldest city in the world, 465 00:38:09,749 --> 00:38:13,788 has been hit over 1 5 times by large earthquakes. 466 00:38:13,829 --> 00:38:15,262 Some believe it was this 467 00:38:15,309 --> 00:38:19,222 that famously brought its walls ''tumbling down''. 468 00:38:22,589 --> 00:38:24,659 Likewise, Petra was abandoned 469 00:38:24,709 --> 00:38:29,908 after an earthquake demolished its irrigation system in AD 36o. 470 00:38:34,749 --> 00:38:37,821 And it continues to this day. 471 00:38:37,869 --> 00:38:41,703 In 2oo3, the city of Bam, famous for its qanats, 472 00:38:41,749 --> 00:38:44,183 was devastated by a massive earthquake 473 00:38:44,229 --> 00:38:47,301 which killed over 3o,ooo people. 474 00:39:00,349 --> 00:39:03,705 It makes you realise that, in effect, much of human history 475 00:39:03,749 --> 00:39:07,788 has centred on a bargain between us and the inner Earth. 476 00:39:09,629 --> 00:39:11,620 Plate boundaries provide access 477 00:39:11,669 --> 00:39:14,627 to resources from deep inside the planet. 478 00:39:19,349 --> 00:39:24,548 But live near one, and every now and then you take a hit. 479 00:39:29,149 --> 00:39:31,902 But even the most advanced of our ancestors 480 00:39:31,949 --> 00:39:35,339 had no way of explaining this strange coincidence. 481 00:39:36,509 --> 00:39:41,708 In fact, it's only in the last 5o years that scientists have finally understood 482 00:39:41,749 --> 00:39:46,823 the bargain that was inadvertently struck all those years ago. 483 00:39:46,869 --> 00:39:51,579 You can see the theory in action in the middle of the Pacific Ocean. 484 00:39:54,469 --> 00:39:58,462 This is Kilauea on Hawaii's Big Island. 485 00:40:01,669 --> 00:40:05,457 It's one of the most active volcanoes on the planet 486 00:40:05,509 --> 00:40:08,706 because it's fed by a chamber of magma deep inside the Earth 487 00:40:08,749 --> 00:40:11,024 called a hot spot. 488 00:40:21,349 --> 00:40:25,820 The hot spot has effectively punched a hole in the Pacific plate - 489 00:40:25,869 --> 00:40:28,861 the piece of the Earth's crust on which Hawaii sits. 490 00:40:29,989 --> 00:40:35,382 But remove the ocean around Hawaii and something strange is revealed - 491 00:40:35,429 --> 00:40:38,546 a chain of mountains stretching along the sea bed 492 00:40:38,589 --> 00:40:41,740 for over 5,oookm. 493 00:40:41,789 --> 00:40:44,861 This line of extinct volcanoes is explained 494 00:40:44,909 --> 00:40:50,506 when you realise that the Pacific plate is continually on the move. 495 00:40:54,029 --> 00:40:57,544 As the plate drifts over this stationary hot spot, 496 00:40:57,589 --> 00:40:59,625 a volcano forms, 497 00:40:59,669 --> 00:41:01,660 but after about a million years, 498 00:41:01,709 --> 00:41:05,099 the moving plate pulls the volcano away from the hot spot. 499 00:41:06,549 --> 00:41:11,498 Meanwhile, another eruption begins, forming a new island. 500 00:41:17,349 --> 00:41:22,946 Today, Kilauea is still growing, but it hasn't got long to go. 501 00:41:22,989 --> 00:41:27,028 In a few thousand years, it will drift away from the hot spot 502 00:41:27,069 --> 00:41:29,663 and eventually disappear beneath the waves. 503 00:41:41,029 --> 00:41:44,738 The Hawaiian islands chain is a beautiful demonstration 504 00:41:44,789 --> 00:41:48,145 of a big idea 505 00:41:48,189 --> 00:41:50,020 that explains why plate boundaries 506 00:41:50,069 --> 00:41:55,860 bring us extraordinary benefits and terrible hazards in equal measure. 507 00:41:57,509 --> 00:42:00,740 It's called plate tectonics. 508 00:42:03,949 --> 00:42:07,862 The key is that all the plates which divide the Earth's surface 509 00:42:07,909 --> 00:42:09,501 are continually on the move. 510 00:42:11,629 --> 00:42:13,984 Where they collide, they crumple the land 511 00:42:14,029 --> 00:42:17,544 to form great mountain ranges, like the Himalayas. 512 00:42:21,189 --> 00:42:23,908 Where they pull apart, 513 00:42:23,949 --> 00:42:26,622 oceans form in the gap. 514 00:42:30,709 --> 00:42:33,542 The friction of this continual movement 515 00:42:33,589 --> 00:42:36,149 means that plate boundaries become melting zones 516 00:42:36,189 --> 00:42:38,145 where minerals are concentrated 517 00:42:38,189 --> 00:42:41,181 and are able to rise towards the surface. 518 00:42:44,309 --> 00:42:47,619 But the flip side is that huge amounts of energy 519 00:42:47,669 --> 00:42:51,025 are concentrated along the plate boundaries. 520 00:42:53,909 --> 00:42:58,664 When one plate slides underneath another, volcanoes form. 521 00:43:10,309 --> 00:43:14,427 When two plates lock together and then suddenly break free, 522 00:43:14,469 --> 00:43:17,381 the jolt causes devastating earthquakes. 523 00:43:23,949 --> 00:43:28,340 So we now know that plate boundaries are so rich in resources 524 00:43:28,389 --> 00:43:31,779 for exactly the reasons they're so dangerous. 525 00:43:34,989 --> 00:43:39,301 Yet the strange thing is this groundbreaking discovery 526 00:43:39,349 --> 00:43:42,227 has made little difference to where we live. 527 00:43:47,509 --> 00:43:49,659 If you look at the plate boundaries, 528 00:43:49,709 --> 00:43:53,543 it's clear that many cities are located close by. 529 00:43:55,349 --> 00:43:59,183 In fact, 1 o of the 2o largest cities in the world 530 00:43:59,229 --> 00:44:01,743 are next to dangerous fault lines. 531 00:44:02,749 --> 00:44:06,458 So why are we still building next to these danger zones? 532 00:44:09,149 --> 00:44:11,822 In the rugged hills of central California 533 00:44:11,869 --> 00:44:14,019 is part of the answer. 534 00:44:18,669 --> 00:44:21,706 And to see it, I'm heading into the skies. 535 00:44:21,749 --> 00:44:24,388 At least, I hope I am. 536 00:44:24,429 --> 00:44:27,580 This is the dinkiest helicopter I've ever been in. 537 00:44:29,429 --> 00:44:31,465 It'll be nice when it's finished. 538 00:44:34,989 --> 00:44:37,298 (MOTOR STARTS) 539 00:45:03,269 --> 00:45:04,748 I'm going to see 540 00:45:04,789 --> 00:45:09,101 perhaps the most famous geological feature on the planet. 541 00:45:09,149 --> 00:45:11,140 And this is the best way to find it. 542 00:45:15,429 --> 00:45:19,820 Yeah, yeah, yeah, this is it. This looks fantastic. 543 00:45:23,829 --> 00:45:28,027 It's this beautiful funnel cut right through these hills here. 544 00:45:28,069 --> 00:45:30,060 That's amazing. 545 00:45:37,429 --> 00:45:40,387 This line of hills with a trench cut through the middle 546 00:45:40,429 --> 00:45:42,659 is the San Andreas Fault. 547 00:45:45,269 --> 00:45:49,057 This fault is a boundary between the North American Plate to the east 548 00:45:49,109 --> 00:45:51,339 and the Pacific Plate to the west. 549 00:45:52,829 --> 00:45:56,708 For 25 million years, they've been grinding past each other 550 00:45:56,749 --> 00:46:00,583 to create the largest earthquake fault in North America. 551 00:46:03,629 --> 00:46:07,417 The San Andreas Fault starts up there in northern California, 552 00:46:07,469 --> 00:46:10,859 then slices down through 7OO miles through here 553 00:46:10,909 --> 00:46:13,104 down to the border with Mexico. 554 00:46:13,149 --> 00:46:16,061 As it goes, it cuts through cities and towns 555 00:46:16,109 --> 00:46:20,022 and passes across a path of roads, bridges, 556 00:46:20,069 --> 00:46:22,424 aqueducts and fibreoptic cables. 557 00:46:27,629 --> 00:46:29,426 If ever there was a fault line 558 00:46:29,469 --> 00:46:33,906 that cut through the very fabric of a modern society, then it's this one. 559 00:46:36,149 --> 00:46:39,824 But a good reason why over 2o million people 560 00:46:39,869 --> 00:46:43,066 carry on living so close to this danger zone 561 00:46:43,109 --> 00:46:46,738 is that this plate boundary has made California rich. 562 00:46:50,869 --> 00:46:53,986 It began with the Californian gold rush. 563 00:46:56,589 --> 00:47:00,377 These nuggets of gold might have been found in streams, 564 00:47:00,429 --> 00:47:04,468 but the gold originally rose in hot mineral-rich fluids 565 00:47:04,509 --> 00:47:06,340 forced up between the plates. 566 00:47:12,229 --> 00:47:17,064 In fact, almost everything that makes California wealthy 567 00:47:17,109 --> 00:47:20,658 is at least partly related to the San Andreas Fault. 568 00:47:22,589 --> 00:47:24,898 Take, for example, the scenery. 569 00:47:24,949 --> 00:47:27,065 It was the colliding plates 570 00:47:27,109 --> 00:47:30,260 that forced up mountains along the Californian coast. 571 00:47:33,749 --> 00:47:39,381 And this dramatic landscape attracts thousands of tourists every year, 572 00:47:39,429 --> 00:47:43,945 who spend an estimated $2 billion on sightseeing alone. 573 00:47:44,989 --> 00:47:46,741 Then there's the wine. 574 00:47:46,789 --> 00:47:49,303 That's partly down to the San Andreas too. 575 00:47:51,149 --> 00:47:53,344 California is mostly desert 576 00:47:53,389 --> 00:47:57,223 but when moist air rolls in off the ocean and hits the mountains, 577 00:47:57,269 --> 00:48:02,138 it rises to form rain that irrigates this otherwise arid landscape. 578 00:48:05,789 --> 00:48:08,257 It's a microclimate that has made this 579 00:48:08,309 --> 00:48:11,028 one of the most productive farming regions in America. 580 00:48:14,709 --> 00:48:19,021 But the ultimate gift of the San Andreas is this. 581 00:48:21,709 --> 00:48:24,382 (HISSING) 582 00:48:29,189 --> 00:48:30,781 Oil. 583 00:48:31,789 --> 00:48:33,302 Black gold. 584 00:48:33,349 --> 00:48:35,624 This is an oil seep, 585 00:48:35,669 --> 00:48:39,582 which is when oil leaks to the surface, just like a natural spring. 586 00:48:41,149 --> 00:48:42,787 (HISSING) 587 00:48:42,829 --> 00:48:46,617 Except this is black and gooey. 588 00:48:46,669 --> 00:48:49,137 Look at that. 589 00:48:49,189 --> 00:48:52,386 1 5O years ago, when the first people were looking for oil, 590 00:48:52,429 --> 00:48:54,704 even the most witless prospector 591 00:48:54,749 --> 00:48:58,901 realised that places like this were a good place to drill. 592 00:49:01,549 --> 00:49:04,905 And drill they did. 593 00:49:06,629 --> 00:49:11,703 Over the years, around 2oo,ooo wells have been sunk here. 594 00:49:19,429 --> 00:49:23,058 Most people probably think of Texas as America's oil state 595 00:49:23,109 --> 00:49:28,786 but California was and still is one of the world's biggest oil producers, 596 00:49:28,829 --> 00:49:31,980 drawing more than 7OO,OOO barrels of crude oil 597 00:49:32,029 --> 00:49:35,385 out of the ground every day. 598 00:49:41,669 --> 00:49:45,378 The oil formed millions of years ago, deep inside the Earth. 599 00:49:45,429 --> 00:49:48,626 But it was the San Andreas Fault which split the rock 600 00:49:48,669 --> 00:49:53,060 and brought it close enough to the surface to be exploited. 601 00:49:58,309 --> 00:50:00,186 So it seems that the San Andreas Fault 602 00:50:00,229 --> 00:50:03,141 has brought California some serious economic benefits. 603 00:50:03,189 --> 00:50:07,307 Its shaping of the land has created the conditions for oil, 604 00:50:07,349 --> 00:50:10,659 for agriculture, for wine and even for tourism. 605 00:50:10,709 --> 00:50:13,587 But how much is that really worth? 606 00:50:18,509 --> 00:50:21,626 The money men have done the sums. 607 00:50:21,669 --> 00:50:27,380 They reckon this state earns around $ 1 oo billion every year 608 00:50:27,429 --> 00:50:29,260 because of the San Andreas Fault. 609 00:50:31,749 --> 00:50:36,948 California's geology is a licence to print money. 610 00:50:39,029 --> 00:50:41,589 Earthquake geologists like me 611 00:50:41,629 --> 00:50:44,780 know that California gets struck by a big seismic shake 612 00:50:44,829 --> 00:50:47,218 every 1 OO to 1 5O years. 613 00:50:47,269 --> 00:50:50,147 And those major quakes are hugely destructive. 614 00:50:50,189 --> 00:50:52,703 That doesn't seem to dampen the spirits 615 00:50:52,749 --> 00:50:56,219 of the number-crunchers that are in these skyscrapers. 616 00:50:56,269 --> 00:50:58,658 It's worked out that in a city like LA, 617 00:50:58,709 --> 00:51:03,863 a major earthquake will cause up to $25O billion worth of damage. 618 00:51:03,909 --> 00:51:06,343 Now, that is a huge sum. 619 00:51:06,389 --> 00:51:10,268 But averaged out over a century, you're still in profit. 620 00:51:10,309 --> 00:51:13,506 You've got $1 OO billion a year coming in, 621 00:51:13,549 --> 00:51:16,427 versus a one-off hit of $25O billion. 622 00:51:16,469 --> 00:51:18,937 That's a gain of 4O to 1 . 623 00:51:18,989 --> 00:51:23,267 Any economist will tell you that's a pretty decent return. 624 00:51:25,669 --> 00:51:27,148 1 o,ooo years 625 00:51:27,189 --> 00:51:31,262 after our ancestors first settled along plate boundaries, 626 00:51:31,309 --> 00:51:35,541 the benefits of living along a fault line are as potent as ever. 627 00:51:41,749 --> 00:51:45,139 The point is that in pure economic terms, 628 00:51:45,189 --> 00:51:49,705 we're still financially better off living along a fault line than not, 629 00:51:49,749 --> 00:51:52,502 even when it's one of the most active in the world. 630 00:51:52,549 --> 00:51:55,427 But the problem that I have with that equation 631 00:51:55,469 --> 00:51:59,178 is that life's not just about money. 632 00:52:07,429 --> 00:52:15,188 Istanbul, the only city in the world to straddle Asia and Europe. 633 00:52:15,229 --> 00:52:18,346 This location at the crossroads of two continents 634 00:52:18,389 --> 00:52:21,904 has made it a trading hub for centuries. 635 00:52:23,789 --> 00:52:26,542 That's why I find it so exciting. 636 00:52:26,589 --> 00:52:29,581 It's a vibrant, bustling, cosmopolitan place. 637 00:52:34,029 --> 00:52:40,468 But Istanbul's location also brings with it great danger. 638 00:52:46,629 --> 00:52:49,462 Nearby lies the North Anatolian Fault, 639 00:52:49,509 --> 00:52:53,502 one of the most seismically active plate boundaries on the planet. 640 00:52:53,549 --> 00:52:58,669 Scientists reckon a major earthquake is due here any time. 641 00:53:02,909 --> 00:53:05,867 There's little doubt that in the very near future, 642 00:53:05,909 --> 00:53:08,946 Istanbul will be struck by a big earthquake. 643 00:53:08,989 --> 00:53:10,820 It's a strange feeling 644 00:53:10,869 --> 00:53:15,943 that this city that I love could be destroyed in my lifetime. 645 00:53:18,029 --> 00:53:20,338 But it doesn't have to be. 646 00:53:23,149 --> 00:53:26,903 Here, they're starting to rewrite the terms 647 00:53:26,949 --> 00:53:29,782 of our ancient bargain with fault lines. 648 00:53:29,829 --> 00:53:33,663 The aim is to enjoy the benefits of living along this plate boundary 649 00:53:33,709 --> 00:53:36,621 without having to pay a price in human life. 650 00:53:40,309 --> 00:53:43,062 Below the waters of the Bosphorus, 651 00:53:43,109 --> 00:53:45,498 the channel that separates Europe from Asia, 652 00:53:45,549 --> 00:53:47,540 is a clue to the solution. 653 00:54:03,189 --> 00:54:05,987 You know, this is such an eerie feeling. 654 00:54:06,029 --> 00:54:08,497 I'm 35m below the level of the Bosphorus 655 00:54:08,549 --> 00:54:10,028 and I'm walking parallel 656 00:54:10,069 --> 00:54:12,629 to one of the most active earthquake zones in the world. 657 00:54:12,669 --> 00:54:17,026 So not the kind of place you expect to find a major engineering project, 658 00:54:17,069 --> 00:54:18,548 and yet that's exactly where 659 00:54:18,589 --> 00:54:23,026 the Turkish authorities decided to build an underground train line. 660 00:54:25,349 --> 00:54:29,467 This tunnel, which will one day link Asia to Europe, 661 00:54:29,509 --> 00:54:31,181 is the deepest tunnel of its kind on Earth 662 00:54:31,229 --> 00:54:33,459 and yet it runs alongside 663 00:54:33,509 --> 00:54:37,502 one of the most dangerous earthquake faults in the world. 664 00:54:41,709 --> 00:54:46,464 These engineers are supremely confident they've got the risks covered. 665 00:54:46,509 --> 00:54:47,988 Through some technical wizardry, 666 00:54:48,029 --> 00:54:50,463 the whole tunnel's designed to absorb the vibrations 667 00:54:50,509 --> 00:54:52,500 of even the largest of earthquakes. 668 00:54:52,549 --> 00:54:54,665 What these guys are doing, effectively, 669 00:54:54,709 --> 00:54:57,348 is confronting the earthquake threat head-on. 670 00:54:59,749 --> 00:55:03,219 This technology won't allow us to stop earthquakes, 671 00:55:03,269 --> 00:55:04,782 but it shows 672 00:55:04,829 --> 00:55:09,459 that if we really want to protect against their consequences, we can. 673 00:55:09,509 --> 00:55:16,028 Unfortunately, in Istanbul, this tunnel is only half the story. 674 00:55:17,749 --> 00:55:21,503 You know, high-tech underground train tunnels are all very well, 675 00:55:21,549 --> 00:55:25,098 but the reality is that most people who'll die in the next earthquake 676 00:55:25,149 --> 00:55:29,222 will die because the buildings that they live and work in collapse. 677 00:55:29,269 --> 00:55:33,342 And in that sense, Istanbul is completely unprepared. 678 00:55:33,389 --> 00:55:35,857 It's reckoned that when the next earthquake comes, 679 00:55:35,909 --> 00:55:38,981 it might bring down a quarter of the city. 680 00:55:39,029 --> 00:55:41,179 And the thing is, it doesn't have to be like that, 681 00:55:41,229 --> 00:55:45,939 because we have the technical know-how to keep buildings standing. 682 00:55:46,949 --> 00:55:51,147 The irony is Istanbul already has a building 683 00:55:51,189 --> 00:55:54,067 that has survived earthquakes for centuries. 684 00:56:02,989 --> 00:56:06,823 This magnificent building is the Hagia Sophia. 685 00:56:06,869 --> 00:56:09,588 It's got to be my favourite place in the city. 686 00:56:09,629 --> 00:56:11,779 For the tourists that come here, 687 00:56:11,829 --> 00:56:14,866 this is a fitting symbol of Istanbul's reputation 688 00:56:14,909 --> 00:56:18,299 as a crossroads of different civilisations. 689 00:56:18,349 --> 00:56:21,978 In its 1,5OO-year history, it's been a church and a mosque 690 00:56:22,029 --> 00:56:24,099 and now a museum. 691 00:56:26,309 --> 00:56:30,666 The Hagia Sophia has stood through more than a dozen earthquakes, 692 00:56:30,709 --> 00:56:33,098 without the benefit of modern technology. 693 00:56:33,149 --> 00:56:37,381 It was built on such a massive, monumental scale 694 00:56:37,429 --> 00:56:42,139 that even the biggest earthquakes never managed to knock it down. 695 00:56:52,349 --> 00:56:55,580 You know, it's no accident that when the earthquake does strike, 696 00:56:55,629 --> 00:56:58,189 the two things that'll probably survive 697 00:56:58,229 --> 00:57:01,778 are one of the oldest buildings in the city and one of the newest. 698 00:57:01,829 --> 00:57:04,741 And that's because they're both structures 699 00:57:04,789 --> 00:57:08,099 that we've decided are worthy of looking after. 700 00:57:11,109 --> 00:57:15,261 Today, we have the technology to protect every building - 701 00:57:15,309 --> 00:57:18,745 whether it's flats, factories or offices... 702 00:57:20,469 --> 00:57:22,539 ...if we choose to. 703 00:57:27,509 --> 00:57:29,704 For 1 o,ooo years, 704 00:57:29,749 --> 00:57:33,458 we've lived with the benefits and the dangers of fault lines. 705 00:57:41,589 --> 00:57:43,739 You know, it's clear that people 706 00:57:43,789 --> 00:57:46,940 are going to continue to live along fault lines - 707 00:57:46,989 --> 00:57:49,423 probably for the next 1 O,OOO years. 708 00:57:49,469 --> 00:57:52,142 But now we have two clear options - 709 00:57:52,189 --> 00:57:55,499 stick with the old regime and take our chances 710 00:57:55,549 --> 00:57:59,701 or embrace the new and take some kind of control. 711 00:57:59,749 --> 00:58:06,188 For the very first time in human history, that choice is ours. 712 00:58:08,509 --> 00:58:11,819 Next time, wind. 713 00:58:11,869 --> 00:58:12,984 For thousands of years, 714 00:58:13,029 --> 00:58:17,102 the wind has shaped the destiny of people across the planet. 715 00:58:17,149 --> 00:58:21,700 It's made fortunes and brought ruin. 716 00:58:21,749 --> 00:58:26,186 Even today, we're still at its mercy.