1 00:00:20,645 --> 00:00:22,814 Just 50 years ago, 2 00:00:23,440 --> 00:00:26,276 we finally ventured to the moon. 3 00:00:40,373 --> 00:00:45,795 For the very first time, we looked back at our own planet. 4 00:00:53,386 --> 00:00:58,683 Since then, the human population has more than doubled. 5 00:01:04,189 --> 00:01:08,610 This series will celebrate the natural wonders that remain 6 00:01:09,569 --> 00:01:12,280 and reveal what we must preserve 7 00:01:12,655 --> 00:01:16,910 to ensure people and nature thrive. 8 00:01:34,677 --> 00:01:35,762 Forests. 9 00:01:37,764 --> 00:01:42,560 Over half of all the world's trees, evergreen and deciduous, 10 00:01:42,811 --> 00:01:45,688 stand in these great assemblies. 11 00:01:54,948 --> 00:01:59,994 For many of us, they are places of mystery and darkness. 12 00:02:08,962 --> 00:02:15,218 They are key to our climate, and home to countless unique species. 13 00:02:19,806 --> 00:02:23,143 In the past, we have destroyed them without hesitation. 14 00:02:25,854 --> 00:02:30,316 Yet, forests do have an astonishing ability to recover. 15 00:02:52,922 --> 00:02:57,051 This is the southern edge of the boreal forest, 16 00:03:00,597 --> 00:03:03,516 the forest that dominates the far north. 17 00:03:07,478 --> 00:03:11,900 It stretches eastwards across Russia for thousands of kilometers, 18 00:03:12,984 --> 00:03:16,696 and now, in the middle of winter, it's largely silent, 19 00:03:18,740 --> 00:03:21,868 seemingly empty of animals of any kind. 20 00:03:26,581 --> 00:03:31,961 But this is the home of an animal so rare it's almost mythical. 21 00:03:56,361 --> 00:03:57,987 A Siberian tiger. 22 00:04:02,659 --> 00:04:04,953 There are less than 600 of them. 23 00:04:22,804 --> 00:04:27,767 These are the most intimate pictures of them in the wild yet taken. 24 00:04:39,988 --> 00:04:46,244 A male Siberian tiger patrols a territory of almost 2,000 square kilometers, 25 00:04:47,078 --> 00:04:50,957 and it has to do so if it is to find enough prey 26 00:04:51,207 --> 00:04:54,961 to keep itself alive during the long winter. 27 00:05:04,178 --> 00:05:09,517 This is an impoverished land where food of any kind is scarce. 28 00:05:14,355 --> 00:05:15,648 A pine cone. 29 00:05:18,401 --> 00:05:23,072 Pine nuts provide vital energy during the winter months. 30 00:05:30,747 --> 00:05:33,541 Wild boar depend on these nuts. 31 00:05:37,128 --> 00:05:41,174 For them, it has to be grab and go, 32 00:05:42,717 --> 00:05:46,596 for they themselves are food for a tiger. 33 00:06:00,818 --> 00:06:05,406 This game of hide-and-seek is played out over vast areas of forest, 34 00:06:05,990 --> 00:06:09,952 as all the animals search for the life-giving stands of pine. 35 00:06:19,921 --> 00:06:24,092 Poaching has taken the Siberian tiger to the brink of extinction, 36 00:06:25,009 --> 00:06:29,680 but, since the 1980s, their numbers have slowly increased. 37 00:06:40,858 --> 00:06:43,152 These rare glimpses reveal 38 00:06:43,444 --> 00:06:50,201 that their future still depends on having vast areas of forest in which to hunt. 39 00:07:00,211 --> 00:07:03,965 The boreal forest extends from Russia in the east, 40 00:07:04,382 --> 00:07:06,509 across Europe, to North America. 41 00:07:08,177 --> 00:07:12,432 It contains 750 billion trees, 42 00:07:13,224 --> 00:07:16,519 and it stores over 40 percent of the world's carbon, 43 00:07:17,353 --> 00:07:21,649 making it a vital element in the fight against climate change. 44 00:07:27,113 --> 00:07:32,201 During the winter, the days are so short and the temperature so low, 45 00:07:32,702 --> 00:07:35,121 that growth is at a standstill. 46 00:07:42,420 --> 00:07:46,340 This far north, the forest can support very few animals 47 00:07:46,424 --> 00:07:48,885 compared to the rain forests of the tropics. 48 00:07:52,763 --> 00:07:57,185 Many are dependent on the supplement to be found in its rivers. 49 00:08:09,489 --> 00:08:14,452 In western Alaska, both in spring and, as now, in autumn, 50 00:08:14,535 --> 00:08:16,913 salmon, having left the ocean, 51 00:08:16,996 --> 00:08:20,625 swim up rivers to reach their ancestral spawning grounds. 52 00:08:22,335 --> 00:08:25,463 Their journey from the sea into the forest represents 53 00:08:25,546 --> 00:08:29,675 the greatest transfer of nutrients from one habitat to another 54 00:08:30,092 --> 00:08:31,802 anywhere on Earth. 55 00:08:38,893 --> 00:08:41,521 The fish are crucial seasonal food 56 00:08:41,687 --> 00:08:44,148 for all the predators that live in this forest. 57 00:08:48,027 --> 00:08:52,573 Bald eagles live here the year round and nest close to the river. 58 00:09:12,969 --> 00:09:15,846 Young eagles, still without white heads, 59 00:09:16,180 --> 00:09:19,600 spend their first years searching for food in the forest. 60 00:09:21,352 --> 00:09:23,854 But, like this four-year-old female, 61 00:09:24,230 --> 00:09:27,400 they're now big enough to try and claim a place on the river. 62 00:09:33,281 --> 00:09:37,785 At first, all she can get are the scraps left by others. 63 00:09:40,997 --> 00:09:44,667 And she can't get even these without a fight. 64 00:10:05,688 --> 00:10:07,857 She will have to look elsewhere. 65 00:10:13,571 --> 00:10:15,656 The boreal forest may be vast, 66 00:10:16,032 --> 00:10:20,703 but the places where the salmon spawn are known to all the predators. 67 00:10:26,626 --> 00:10:31,547 As the rivers begin to freeze over, competition becomes even more intense. 68 00:10:43,142 --> 00:10:47,188 This youngster is lucky, but her success is noticed immediately. 69 00:11:22,181 --> 00:11:24,183 She does have one advantage. 70 00:11:27,061 --> 00:11:30,481 Females, even when young, are larger than the males. 71 00:11:31,899 --> 00:11:33,734 And here, size matters. 72 00:12:16,610 --> 00:12:18,237 As winter advances, 73 00:12:18,696 --> 00:12:24,118 young and old have to meet the challenge of the intense cold. 74 00:12:26,036 --> 00:12:29,457 If she can survive, she will have gained a place 75 00:12:29,749 --> 00:12:33,878 in one of the greatest and harshest forests on Earth. 76 00:12:47,141 --> 00:12:48,851 A little further south 77 00:12:48,934 --> 00:12:52,521 stand the last of the great redwood forests. 78 00:12:56,484 --> 00:13:01,739 Not so long ago, these great trees grew throughout the Pacific Northwest. 79 00:13:09,205 --> 00:13:12,249 Now, only five percent of them remain. 80 00:13:22,134 --> 00:13:24,637 Here, conditions are less harsh. 81 00:13:25,471 --> 00:13:28,933 Winds bring in warm, humid air from the Pacific Ocean, 82 00:13:29,016 --> 00:13:32,520 so the trees are able to grow the year round. 83 00:13:35,856 --> 00:13:39,193 Hidden in the vegetation of the moist forest floor 84 00:13:39,276 --> 00:13:41,987 is a richly populated underworld. 85 00:13:48,452 --> 00:13:51,372 A male rough-skinned newt. 86 00:13:54,583 --> 00:13:58,170 Every spring, he is driven by a mysterious urge 87 00:13:58,462 --> 00:14:02,007 to return to the pool where he hatched as a tadpole. 88 00:14:06,136 --> 00:14:07,972 And he needs to get there quickly. 89 00:14:12,309 --> 00:14:14,520 Because there are lots of others like him... 90 00:14:19,525 --> 00:14:21,652 with exactly the same idea. 91 00:14:44,008 --> 00:14:45,968 They're all searching for a female, 92 00:14:47,261 --> 00:14:52,099 but trekking across hundreds of meters of old-growth forest is not easy. 93 00:15:00,316 --> 00:15:02,067 There is strong competition. 94 00:15:11,785 --> 00:15:15,414 And the female is anxious to get going. 95 00:15:21,420 --> 00:15:23,422 Once paired, he hangs on, 96 00:15:23,505 --> 00:15:27,718 for she may take several hours to discharge all her eggs. 97 00:15:34,600 --> 00:15:37,770 Other males are only too eager to displace him if they can. 98 00:15:48,739 --> 00:15:50,658 Competition is so vigorous 99 00:15:50,741 --> 00:15:53,953 that the females in the center of these writhing balls 100 00:15:54,203 --> 00:15:56,872 have been known to drown for lack of air. 101 00:16:08,217 --> 00:16:11,387 But her first partner maintains his grip. 102 00:16:13,681 --> 00:16:16,600 Within weeks, their tadpoles will hatch. 103 00:16:19,561 --> 00:16:24,483 And none too soon, for the forest is about to change dramatically. 104 00:16:30,072 --> 00:16:34,118 By the end of the summer, the sun has baked the forest so intensely 105 00:16:34,576 --> 00:16:36,996 that they are as dry as tinder. 106 00:17:00,978 --> 00:17:03,272 Strong winds drive the flames, 107 00:17:04,857 --> 00:17:08,694 and temperatures rise to 700 degrees Celsius. 108 00:18:05,417 --> 00:18:09,671 Its aftermath is seemingly total destruction. 109 00:18:23,560 --> 00:18:26,814 The wind, scouring the newly exposed forest floor, 110 00:18:27,272 --> 00:18:29,358 kicks up dust devils of ash. 111 00:18:43,330 --> 00:18:46,667 The ground appears to be devoid of life. 112 00:19:03,475 --> 00:19:06,186 But the forest is far from dead. 113 00:19:16,155 --> 00:19:18,073 Within only a few months, 114 00:19:18,365 --> 00:19:22,286 flowers and tree seedlings will rise from the soil. 115 00:19:32,171 --> 00:19:37,801 Many, in fact, would not have germinated had they not received a baptism of fire. 116 00:19:55,569 --> 00:19:58,989 Light streaming down through the newly opened canopy 117 00:19:59,198 --> 00:20:02,826 provides the energy for a surge of new growth. 118 00:20:15,964 --> 00:20:19,218 The older, well-established redwoods have survived, 119 00:20:19,551 --> 00:20:22,638 protected by their thick, fire-resistant bark. 120 00:20:29,102 --> 00:20:34,775 This natural resilience is essential to the continued health of these forests. 121 00:20:47,287 --> 00:20:51,041 Most forests, however, cannot recover on their own. 122 00:20:54,461 --> 00:20:57,673 Many are helped to recover by animals. 123 00:21:02,261 --> 00:21:05,764 The trees and their inhabitants are interdependent. 124 00:21:10,394 --> 00:21:13,397 And nowhere is this dependence more apparent 125 00:21:13,689 --> 00:21:16,108 than in India's Western Ghats. 126 00:21:17,526 --> 00:21:19,653 This globally important habitat 127 00:21:19,861 --> 00:21:23,699 contains a third of all animal species found in India. 128 00:21:35,419 --> 00:21:37,504 Lion-tailed macaques. 129 00:21:43,302 --> 00:21:46,013 They feed on the fruits of many kinds of tree, 130 00:21:46,680 --> 00:21:49,683 and, in doing so, they distribute the seeds, 131 00:21:49,766 --> 00:21:52,269 which will emerge unscathed with their droppings. 132 00:21:57,316 --> 00:21:59,985 But few monkeys travel very far. 133 00:22:01,862 --> 00:22:05,699 If plants are to distribute their seeds across great distances, 134 00:22:06,366 --> 00:22:08,744 they need another kind of transport. 135 00:22:21,923 --> 00:22:22,923 Wings. 136 00:22:44,571 --> 00:22:48,784 Great hornbills have wings that are almost two meters across, 137 00:22:49,117 --> 00:22:53,789 and they enable the birds to travel long distances in search of food. 138 00:22:57,292 --> 00:23:01,755 Hornbills feed on the fruit of 40 or so different kinds of trees, 139 00:23:02,172 --> 00:23:05,175 and transport the indigestible seeds they contain 140 00:23:05,759 --> 00:23:07,552 all over the Western Ghats. 141 00:23:12,724 --> 00:23:17,396 So, it's to the trees' advantage to attract the hornbill's attention. 142 00:23:33,578 --> 00:23:36,289 The figs themselves, although they taste nice, 143 00:23:36,498 --> 00:23:38,542 are not, in fact, very nutritious, 144 00:23:38,875 --> 00:23:41,795 so the hornbills have to eat great quantities of them. 145 00:23:47,634 --> 00:23:49,010 It can be tiring work. 146 00:23:52,305 --> 00:23:54,182 But it's not a free-for-all. 147 00:23:59,521 --> 00:24:03,733 A single fig tree in fruit attracts great numbers of hornbills. 148 00:24:12,200 --> 00:24:14,786 Competition between them is intense. 149 00:24:32,471 --> 00:24:36,850 This aerial jousting between males has never been filmed before 150 00:24:37,434 --> 00:24:40,145 and its purpose is not really understood. 151 00:24:42,189 --> 00:24:45,525 It may be that the birds are simply squabbling over food, 152 00:24:46,443 --> 00:24:48,778 but it seems rather more than that. 153 00:25:22,229 --> 00:25:25,982 The winner is able to demonstrate his strength and skill 154 00:25:26,274 --> 00:25:27,859 to visiting females. 155 00:25:37,536 --> 00:25:41,456 The males certainly seem keen to ingratiate themselves. 156 00:25:51,174 --> 00:25:54,844 It's particularly important for hornbills to get the best pairing 157 00:25:55,178 --> 00:25:59,015 because, once established, the bond between male and female 158 00:25:59,266 --> 00:26:01,309 will last a lifetime. 159 00:26:09,025 --> 00:26:11,653 The forest also benefits from these squabbles, 160 00:26:12,237 --> 00:26:14,406 because even a defeated hornbill 161 00:26:14,489 --> 00:26:18,660 will spread seeds over wide areas as he searches for his next meal. 162 00:26:25,166 --> 00:26:28,545 The relationship between trees and animals in a forest 163 00:26:28,753 --> 00:26:30,755 is not always so harmonious. 164 00:26:33,800 --> 00:26:37,554 This is Africa's largest forest, the Miombo, 165 00:26:38,013 --> 00:26:40,432 named after one of its common trees. 166 00:26:42,851 --> 00:26:45,520 It stretches for over a thousand miles, 167 00:26:45,604 --> 00:26:48,982 from Angola in the west to Mozambique in the east. 168 00:26:59,284 --> 00:27:00,910 At the height of the dry season, 169 00:27:01,077 --> 00:27:04,998 the Miombo attracts animals from all across southern Africa. 170 00:27:17,719 --> 00:27:22,307 Elephants prefer grass if they can get it. It's very nutritious. 171 00:27:26,519 --> 00:27:27,687 In its absence, 172 00:27:27,854 --> 00:27:32,108 they browse on the abundant leaves and branches of the Miombo. 173 00:27:39,658 --> 00:27:42,494 But they're not the only hungry ones here. 174 00:27:47,749 --> 00:27:49,417 These mopane worms 175 00:27:49,751 --> 00:27:52,295 are not worms, of course, but caterpillars. 176 00:27:56,716 --> 00:27:59,969 They hatch simultaneously in huge numbers. 177 00:28:05,475 --> 00:28:08,269 And just as the forest is putting out new leaves, 178 00:28:08,561 --> 00:28:09,813 they begin their attack. 179 00:28:24,494 --> 00:28:26,121 They feed so voraciously 180 00:28:26,705 --> 00:28:31,376 that in just six weeks they increase their size 40 times. 181 00:28:36,506 --> 00:28:40,051 By the time they're fully developed, this million-strong army 182 00:28:40,301 --> 00:28:43,596 will have stripped the entire forest of its foliage. 183 00:28:50,395 --> 00:28:52,731 But the Miombo bounces back. 184 00:28:55,024 --> 00:28:56,401 With the caterpillars gone, 185 00:28:56,609 --> 00:28:59,946 the trees produce a second growth of leaves. 186 00:29:06,453 --> 00:29:09,831 This fresh feast then attracts elephants. 187 00:29:14,961 --> 00:29:17,380 They are less fussy than the caterpillars. 188 00:29:19,174 --> 00:29:21,468 They will eat every part of the tree. 189 00:29:23,219 --> 00:29:28,933 And a hungry elephant can munch through 200 kilos of vegetation in a day. 190 00:29:36,608 --> 00:29:39,736 Yet, even this destruction has its benefits. 191 00:29:41,404 --> 00:29:46,493 It shapes the forest in a way that helps one of Africa's most endangered animals. 192 00:29:50,371 --> 00:29:51,581 Hunting dogs. 193 00:29:56,085 --> 00:30:00,131 They're seen most frequently, and most easily, on grasslands. 194 00:30:00,757 --> 00:30:04,844 But, in fact, these open forests are their preferred habitat. 195 00:30:11,017 --> 00:30:13,478 Browsing elephants open up a forest, 196 00:30:13,937 --> 00:30:17,106 and that attracts the animals on which the dogs prey. 197 00:30:59,065 --> 00:31:03,319 For the dogs, the Miombo forest is perfect hunting country. 198 00:31:07,365 --> 00:31:11,578 And it's also an excellent place in which to bring up pups. 199 00:31:22,088 --> 00:31:24,716 The pups greet the adults returning from a hunt 200 00:31:24,883 --> 00:31:26,217 with great excitement. 201 00:31:33,308 --> 00:31:34,309 Food. 202 00:31:44,819 --> 00:31:49,657 The first three months of the pups' lives are spent sheltering underground. 203 00:31:55,038 --> 00:31:57,332 Now, they are confident enough 204 00:31:57,415 --> 00:31:59,834 to stay out in the open for much of the time. 205 00:32:01,878 --> 00:32:05,131 And then, like all puppies, they have fun. 206 00:32:21,856 --> 00:32:24,359 Playing is important for the youngsters, 207 00:32:24,442 --> 00:32:28,363 for as they do so, they establish the social bonds 208 00:32:28,529 --> 00:32:31,908 that they will need when they start to hunt together as a team. 209 00:32:43,628 --> 00:32:46,923 The Miombo has always been important for hunting dogs, 210 00:32:47,340 --> 00:32:51,594 both as a place to find prey and as a refuge. 211 00:32:56,683 --> 00:32:58,476 Never has it been more crucial 212 00:32:58,768 --> 00:33:02,647 for the survival of this endangered species than now. 213 00:33:07,276 --> 00:33:10,697 But they will only survive if other creatures are here 214 00:33:11,197 --> 00:33:13,741 to create the kind of habitat they need. 215 00:33:22,000 --> 00:33:23,835 Madagascar has a forest 216 00:33:24,043 --> 00:33:27,839 dominated uniquely by one of the oddest of trees. 217 00:33:29,716 --> 00:33:30,800 Baobabs. 218 00:33:36,639 --> 00:33:40,643 The island has been isolated for over 80 million years. 219 00:33:41,936 --> 00:33:45,356 During that immensity of time, its animals and plants 220 00:33:45,440 --> 00:33:49,652 have evolved into forms quite different from any elsewhere. 221 00:33:54,198 --> 00:33:58,161 This makes them one of the most precious forests on our planet. 222 00:34:09,005 --> 00:34:13,301 This is not a monkey, but a distant relative, a lemur, 223 00:34:13,676 --> 00:34:16,888 and there are at least 40 different kinds of lemurs, 224 00:34:17,305 --> 00:34:20,975 all unique to Madagascar and all endangered. 225 00:34:23,061 --> 00:34:25,396 Lemurs are crucial to the forest. 226 00:34:26,481 --> 00:34:30,234 Without them, some species of tree cannot survive. 227 00:34:36,282 --> 00:34:40,286 The forest even has its own specialized lemur hunter. 228 00:34:50,254 --> 00:34:52,298 It's Madagascar's top predator, 229 00:34:53,508 --> 00:34:56,427 and its presence is cause for alarm. 230 00:35:01,349 --> 00:35:03,851 It can grow to a length of one and a half meters, 231 00:35:04,852 --> 00:35:07,563 and it's very seldom seen in the wild. 232 00:35:09,774 --> 00:35:10,774 It's a fossa. 233 00:35:20,076 --> 00:35:22,203 For most of the year, fossas are solitary, 234 00:35:22,703 --> 00:35:27,125 but in the breeding season, they assemble in a way that is all their own. 235 00:35:30,211 --> 00:35:35,216 Each mature female takes up residence in a special mating tree. 236 00:35:49,230 --> 00:35:53,442 Half a dozen or so male fossas have gathered in the forest below it, 237 00:35:56,696 --> 00:35:58,781 but she is clearly occupied. 238 00:36:02,118 --> 00:36:04,495 So, one of the males leaves his scent. 239 00:36:07,248 --> 00:36:09,792 A visiting card, just to show that he called. 240 00:36:24,015 --> 00:36:28,269 He will just have to wait around and see whether she takes any notice. 241 00:36:34,066 --> 00:36:37,153 Her present engagement can last all night. 242 00:36:42,992 --> 00:36:46,829 With its top predators distracted, the rest of the forest animals 243 00:36:46,913 --> 00:36:50,791 can go about their normal nightly business undisturbed. 244 00:36:54,045 --> 00:36:58,758 These are immature leaf bugs, a species found only here in Madagascar. 245 00:37:01,677 --> 00:37:04,764 Why they have this extraordinary shape, no one knows. 246 00:37:09,185 --> 00:37:10,978 They feed on tree sap, 247 00:37:11,395 --> 00:37:15,191 absorbing the part they need and excreting the rest as a sweet liquid 248 00:37:15,441 --> 00:37:19,570 sometimes known, perhaps flatteringly, as honeydew. 249 00:37:25,618 --> 00:37:31,707 And honeydew, in turn, provides food for a particular species of small lemur. 250 00:37:43,803 --> 00:37:47,390 The gray mouse lemur is only 15 centimeters long, 251 00:37:47,473 --> 00:37:50,476 one of the smallest primates in the world. 252 00:37:55,106 --> 00:37:58,943 It's very active and needs an energy-packed food. 253 00:38:01,320 --> 00:38:03,739 And while the sugar drops are clearly delicious, 254 00:38:04,198 --> 00:38:05,700 they're not very sustaining. 255 00:38:10,329 --> 00:38:13,833 So, she's not going to let a single drop go to waste. 256 00:38:38,774 --> 00:38:42,361 The male fossas below are still awaiting their turn. 257 00:38:45,239 --> 00:38:47,783 So, having eaten as much as she can, 258 00:38:48,075 --> 00:38:51,203 she retreats to the safety of her nest hole 259 00:38:51,329 --> 00:38:53,748 to sleep during the daylight hours. 260 00:39:16,187 --> 00:39:19,357 Things are not looking so satisfactory on the ground 261 00:39:19,565 --> 00:39:21,359 around the fossas' mating tree. 262 00:39:26,655 --> 00:39:29,784 The pair above are clearly still engaged. 263 00:39:33,704 --> 00:39:38,417 He will either have to find another mating tree or be very patient. 264 00:39:46,258 --> 00:39:48,803 But he may well fail altogether. 265 00:39:51,514 --> 00:39:56,435 A third of Madagascar's fossas have disappeared in the last 20 years, 266 00:39:57,395 --> 00:40:01,982 a result of the continued destruction of their forests by people. 267 00:40:06,487 --> 00:40:08,239 Since these pictures were recorded, 268 00:40:08,781 --> 00:40:11,700 this forest, and the unique life it once contained, 269 00:40:12,159 --> 00:40:14,203 have disappeared altogether. 270 00:40:19,792 --> 00:40:24,296 Only three percent of Madagascar's dry forest remains. 271 00:40:31,887 --> 00:40:34,181 Worldwide, we have now destroyed 272 00:40:34,265 --> 00:40:38,144 over half of the forests that once flourished on our planet. 273 00:40:41,647 --> 00:40:44,733 Not only are we losing the animals that once lived in them, 274 00:40:45,317 --> 00:40:49,029 we are also changing the climate of the entire globe. 275 00:41:02,001 --> 00:41:05,004 But our planet's forests, if given the chance, 276 00:41:05,171 --> 00:41:07,965 are almost unbelievably resilient. 277 00:41:13,012 --> 00:41:16,724 Perhaps the best proof we have of their ability to recover 278 00:41:17,016 --> 00:41:21,020 can be seen on the site of one of our greatest disasters. 279 00:41:29,403 --> 00:41:30,403 Chernobyl. 280 00:41:36,410 --> 00:41:42,708 In 1986, one of the four reactors at the Chernobyl nuclear plant exploded. 281 00:41:44,543 --> 00:41:49,215 It turned this utopian vision of the future into a ghost town. 282 00:41:55,721 --> 00:42:00,100 Over 100,000 people were immediately evacuated, 283 00:42:00,184 --> 00:42:01,477 never to return. 284 00:42:08,734 --> 00:42:14,657 The fallout zone was declared uninhabitable for the next 20,000 years. 285 00:42:25,417 --> 00:42:29,755 Yet despite the radiation, there has been a remarkable recovery. 286 00:42:56,740 --> 00:42:58,576 Within only a decade, 287 00:42:59,076 --> 00:43:02,538 vegetation began to germinate in the ruined city. 288 00:43:09,128 --> 00:43:14,800 And as the forest reestablished itself, animals began to appear. 289 00:43:39,617 --> 00:43:43,787 At first it was thought that these were rare visitors, 290 00:43:48,500 --> 00:43:51,545 but it soon became clear that the former city 291 00:43:51,754 --> 00:43:56,175 was occupied by an established and thriving wild community. 292 00:44:23,410 --> 00:44:25,496 Within only 20 years, 293 00:44:25,579 --> 00:44:28,415 science has recorded populations of animals 294 00:44:28,624 --> 00:44:31,585 similar to that in the wilder parts of Europe. 295 00:44:35,714 --> 00:44:40,302 Roe deer are now a common sight, wandering through the suburbs. 296 00:44:48,560 --> 00:44:51,522 Herds of the endangered Przewalski's horse 297 00:44:51,730 --> 00:44:54,566 now roam freely through the once busy city. 298 00:44:57,653 --> 00:44:59,405 Most surprising of all perhaps, 299 00:45:00,030 --> 00:45:03,409 the top predator of these forests has reappeared. 300 00:45:06,161 --> 00:45:07,246 Wolves. 301 00:45:11,375 --> 00:45:13,752 Hunters like these would only return 302 00:45:13,919 --> 00:45:18,006 if their prey and the surrounding forest is also thriving. 303 00:45:20,217 --> 00:45:22,136 Now, studies have shown 304 00:45:22,302 --> 00:45:27,975 that there are seven times more wolves inside the exclusion zone than outside it. 305 00:45:36,525 --> 00:45:38,569 No unprotected human being 306 00:45:38,652 --> 00:45:41,864 can stay here for long without lethal risk. 307 00:45:44,491 --> 00:45:46,160 But in driving us out, 308 00:45:46,744 --> 00:45:50,956 the radiation has created space for wildlife to return. 309 00:45:59,339 --> 00:46:05,262 The dramatic recolonization of Chernobyl in the space of only 30 years 310 00:46:05,596 --> 00:46:09,767 is proof of forests' extraordinary resilience. 311 00:46:21,570 --> 00:46:25,073 If we choose to give forests time and space, 312 00:46:25,491 --> 00:46:27,534 they could reclothe the earth 313 00:46:27,868 --> 00:46:31,663 with much of the rich and varied communities of animals and plants 314 00:46:32,039 --> 00:46:35,250 of which we have, so recently, robbed it. 315 00:46:39,421 --> 00:46:46,136 A future with more forests is key to the resilience of our planet. 316 00:47:03,987 --> 00:47:06,114 Please visit ourplanet.com 317 00:47:06,406 --> 00:47:10,744 to discover what we need to do now to restore our forests. 318 00:47:13,372 --> 00:47:19,211 ♪ I can hear the whole world Singing together ♪ 319 00:47:21,880 --> 00:47:27,719 ♪ I can hear the whole world Say it's now or never ♪ 320 00:47:30,639 --> 00:47:34,893 ♪ 'Cause it's not too late If we change our ways ♪ 321 00:47:34,977 --> 00:47:38,605 ♪ And connect the dots to our problems ♪ 322 00:47:38,856 --> 00:47:44,695 ♪ I can hear the whole world Say we're in this together ♪ 323 00:47:45,028 --> 00:47:46,738 ♪ We're in this together ♪