0:11
I would like to invite you to come along on a visit to a dark continent. It is the continent hidden under the surface of the earth. It is largely unexplored, poorly understood, and the stuff of legends. But it is made also of dramatic landscapes like this huge underground chamber, and it is rich with surprising biological and mineralogical worlds.
0:37
Thanks to the efforts of intrepid voyagers in the last three centuries -- actually, we know also thanks to satellite technology, of course -- we know almost every single square meter of our planet's surface. However, we know still very little about what is hidden inside the earth. Because a cave landscape, like this deep shaft in Italy, is hidden, the potential of cave exploration -- the geographical dimension -- is poorly understood and unappreciated. Because we are creatures living on the surface, our perception of the inner side of the planet is in some ways skewed, as is that of the depth of the oceans or of the upper atmosphere.
1:22
However, since systematic cave exploration started about one century ago, we know actually that caves exist in every continent of the world. A single cave system, like Mammoth Cave, which is in Kentucky, can be as long as more than 600 kilometers. And an abyss like Krubera Voronya, which is in the Caucasus region, actually the deepest cave explored in the world, can go as far as more than 2,000 meters below the surface. That means a journey of weeks for a cave explorer.
1:58
Caves form in karstic regions. So karstic regions are areas of the world where the infiltrating water along cracks, fractures, can easily dissolve soluble lithologies, forming a drainage system of tunnels, conduits -- a three-dimensional network, actually. Karstic regions cover almost 20 percent of the continents' surface, and we know actually that speleologists in the last 50 years have explored roughly 30,000 kilometers of cave passages around the world, which is a big number. But geologists have estimated that what is still missing, to be discovered and mapped, is something around 10 million kilometers.
2:46
That means that for each meter of a cave that we already know, that we have explored, there are still some tens of kilometers of undiscovered passages. That means that this is really an endless continent, and we will never be able to explore it completely. And this estimation is made without considering other types of caves, like, for example, inside glaciers or even volcanic caves, which are not karstic, but are formed by lava flows. And if we have a look at other planets like, for example, Mars, you will see that this characteristic is not so specific of our home planet. However, I will show to you now that we do not need to go to Mars to explore alien worlds.
3:34
I'm a speleologist, that means a cave explorer. And I started with this passion when I was really young in the mountains not far from my hometown in North Italy, in the karstic regions of the Alps and the Dolomites. But soon, the quest for exploration brought me to the farthest corner of the planet, searching for new potential entrances of this undiscovered continent. And in 2009, I had the opportunity to visit the tepui table mountains, which are in the Orinoco and Amazon basins. These massifs enchanted me from the first time I saw them. They are surrounded by vertical, vertiginous rock walls with silvery waterfalls that are lost in the forest. They really inspired in me a sense of wilderness, with a soul older than millions and millions of years. And this dramatic landscape inspired among other things also Conan Doyle's "The Lost World" novel in 1912. And they are, really, a lost world. Scientists consider those mountains as islands in time, being separated from the surrounding lowlands since tens of millions of years ago. They are surrounded by up to 1,000-meter-high walls, resembling a fortress, impregnable by humans. And, in fact, only a few of these mountains have been climbed and explored on their top.
5:03
These mountains contain also a scientific paradox: They are made by quartz, which is a very common mineral on the earth's crust, and the rock made up by quartz is called quartzite, and quartzite is one of the hardest and least soluble minerals on earth. So we do not expect at all to find a cave there. Despite this, in the last 10 years, speleologists from Italy, Slovakia, Czech Republic, and, of course, Venezuela and Brazil, have explored several caves in this area. So how can it be possible?
5:39
To understand this contradiction, we have to consider the time factor, because the history of the tepuis is extremely long, starting about 1.6 billion years ago with the formation of the rock, and then evolving with the uplift of the region 150 million years ago, after the disruption of the Pangaea supercontinent and the opening of the Atlantic Ocean. So you can imagine that the water had tens or even hundreds of millions of years to sculpt the strangest forms on the tepuis' surfaces, but also to open the fractures and form stone cities, rock cities, fields of towers which are characterized in the famous landscape of the tepuis. But nobody could have imagined what was happening inside a mountain in so long a time frame.
6:31
And so I was focusing in 2010 on one of those massifs, the Auyán-tepui, which is very famous because it hosts Angel Falls, which is the highest waterfall in the world -- about 979 meters of vertical drop. And I was searching for hints of the existence of cave systems through satellite images, and finally we identified an area of collapses of the surface -- so, big boulders, rock piles -- and that means that there was a void below. It was a clear indication that there was something inside the mountain.
7:07
So we did several attempts to reach this area, by land and with a helicopter, but it was really difficult because -- you have to imagine that these mountains are covered by clouds most of the year, by fog. There are strong winds, and there are almost 4,000 millimeters of rainfall per year, so it's really, really difficult to find good conditions. And only in 2013 we finally landed on the spot and we started the exploration of the cave.
7:39
The cave is huge. It's a huge network under the surface of the tepui plateau, and in only ten days of expedition, we explored more than 20 kilometers of cave passages. And it's a huge network of underground rivers, channels, big rooms, extremely deep shafts.
8:03
So it's really an incredible place. And we named it Imawarì Yeuta. That means, in the Pemón indigenous language, "The House of the Gods." You have to imagine that indigenous people have never been there. It was impossible for them to reach this area. However, there were legends about the existence of a cave in the mountain. So when we started the exploration, we had to explore with a great respect, both because of the religious beliefs of the indigenous people, but also because it was really a sacred place, because no human had entered there before. So we had to use special protocols to not contaminate the environment with our presence, and we tried also to share with the community, with the indigenous community, our discoveries.
8:50
And the caves represent, really, a snapshot of the past. The time needed for their formation could be as long as 50 or even 100 million years, which makes them possibly the oldest caves that we can explore on earth. What you can find there is really evidence of a lost world.
9:16
When you enter a quartzite cave, you have to completely forget what you know about caves -- classic limestone caves or the touristic caves that you can visit in several places in the world. Because what seems a simple stalactite here is not made by calcium carbonate, but is made by opal, and one of those stalactites can require tens of millions of years to be formed. But you can find even stranger forms, like these mushrooms of silica growing on a boulder. And you can imagine our talks when we were exploring the cave. We were the first entering and discovering those unknown things, things like those monster eggs. And we were a bit scared because it was all a discovery, and we didn't want to find a dinosaur. We didn't find a dinosaur.
10:07
(Laughter)
10:09
Anyway, actually, we know that this kind of formation, after several studies, we know that these kinds of formations are living organisms. They are bacterial colonies using silica to build mineral structures resembling stromatolites. Stromatolites are some of the oldest forms of life that we can find on earth. And here in the tepuis, the interesting thing is that these bacteria colonies have evolved in complete isolation from the external surface, and without being in contact with humans. They have never been in contact with humans. So the implications for science are enormous, because here you could find, for example, microbes that could be useful to resolve diseases in medicine, or you could find even a new kind of material with unknown properties. And, in fact, we discovered in the cave a new mineral structure for science, which is rossiantonite, a phosphate-sulfate.
11:10
So whatever you find in the cave, even a small cricket, has evolved in the dark in complete isolation. And, really, everything that you can feel in the cave are real connections between the biological and the mineralogical world. So as we explore this dark continent and discover its mineralogical and biological diversity and uniqueness, we will find probably clues about the origin of life on our planet and on the relationship and evolution of life in relationship with the mineral world. What seems only a dark, empty environment could be in reality a chest of wonders full of useful information.
12:01
With a team of Italian, Venezuelan and Brazilian speleologists, which is called La Venta Teraphosa, we will be back soon to Latin America, because we want to explore other tepuis in the farthest areas of the Amazon. There are still very unknown mountains, like Marahuaca, which is almost 3,000 meters high above sea level, or Aracà, which is in the upper region of Rio Negro in Brazil. And we suppose that we could find there even bigger cave systems, and each one with its own undiscovered world.
12:37
Thank you.
12:38
(Applause)
12:44
Bruno Giussani: Thank you, Francesco. Give me that to start so we don't forget. Francesco, you said we don't need to go to Mars to find alien life, and indeed, last time we spoke, you were in Sardinia and you were training European astronauts. So what do you, a speleologist, tell and teach to the astronauts?
13:00
Francesco Sauro: Yeah, we are -- it's a program of training for not only European, but also NASA, Roskosmos, JAXA astronauts, in a cave. So they stay in a cave for about one week in isolation. They have to work together in a real, real dangerous environment, and it's a real alien environment for them because it's unusual. It's always dark. They have to do science. They have a lot of tasks. And it's very similar to a journey to Mars or the International Space Station.
13:28
BG: In principle. FS: Yes.
13:29
BG: I want to go back to one of the pictures that was in your slide show, and it's just representative of the other photos --
13:35
Weren't those photos amazing? Yeah?
13:38
Audience: Yeah!
13:39
(Applause)
13:43
FS: I have to thank the photographers from the team La Venta, because all of those photos are from the photographers.
13:50
BG: You bring, actually, photographers with you in the expedition. They're professionals, they're speleologists and photographers. But when I look at these pictures, I wonder: there is zero light down there, and yet they look incredibly well-exposed. How do you take these pictures? How do your colleagues, the photographers, take these pictures?
14:09
FS: Yeah. They are working in a darkroom, basically, so you can open the shutter of the camera and use the lights to paint the environment.
14:16
BG: So you're basically --
14:17
FS: Yes. You can even keep the shutter open for one minute and then paint the environment. The final result is what you want to achieve.
14:24
BG: You spray the environment with light and that's what you get. Maybe we can try this at home someday, I don't know.
14:30
(Laughter)
14:31
BG: Francesco, grazie. FS: Grazie.
14:32
(Applause)
0:11
我想邀请在座的各位 和我一起 去探索一片黑暗的大陆。 这片大陆 隐藏于地表之下。 大部分地方无人踏足， 不为人知，充满传奇色彩。 那里有鬼斧神工的奇观， 比如这个硕大的地下大厅， 也充满了令人惊奇的生物和矿物。
0:37
多亏三个世纪以来英勇无畏的探险家们—— 当然，也少不了卫星技术的帮助—— 我们几乎对地球表面的 每一寸土地都了如指掌。 然而，对于隐藏在地表以下的世界， 我们却知之甚少。 因为这些巨大的洞穴， 像这个位于意大利的深坑，深埋地下， 而洞穴考察——从地理学方面而言——的潜力 还得不到足够的重视和认可。 因为我们是居住在地表的生物， 我们对于地球内部的看法 在某些方面是不正确的， 就如同我们对大洋深处 和近地空间的看法一样。
1:22
尽管如此，由于系统的洞穴勘探 开始于1个世纪前， 我们了解到每一块大陆上都有洞穴存在。 单洞穴系统，比如肯塔基州的猛犸洞， 长度可以绵延超过600公里。 而像位于高加索地区的库鲁伯亚拉洞穴， 是迄今为止发现的最深的洞穴， 深度超过2000米。 意味着洞穴探险家要花数周时间才能到底。
1:58
（这些是）喀斯特地区形成的洞穴。 所谓喀斯特地区，是指这些区域， 那里的水顺着岩石缝隙流入地下， 对可溶性岩石产生溶蚀作用， 形成纵横交错、暗渠遍布的排水系统—— 实际上是一种三维立体网络。 喀斯特地区几乎覆盖了陆地表面的20%， 在过去的50年里，洞穴学家们 在全世界探索了差不多3万公里的洞穴通道， 这是个了不起的数字。 但地质学家估计，那些没被发现的， 没有被探明和标注的（洞穴通道）， 差不多还有1000万公里。
2:46
也就是说，那些已经被发现的洞穴， 其中被勘探过的每一米， 都对应数十公里尚未被发现的洞穴通道。 可以说这是一片没有尽头的陆地， 我们永远也不可能将它走完。 而这一估算还未包括其他种类的洞穴， 比如说，冰川洞穴，或者火山洞穴， （火山洞穴）不是喀斯特洞穴， 而是由熔岩流动形成的。 如果我们将目光转向其他行星，比如火星， 可以看到这些（地质）特征 并不是地球独有的。 当然，我们不用前往火星 去探索外星人的世界。
3:34
我是一名洞穴学家， 我的工作是勘探洞穴。 我这个爱好在我很小的时候就形成了， 当时是在离我家不远， 意大利北部的山区里， 位于阿尔卑斯山和 白云石山的喀斯特地区。 很快，对于勘探的追求 将我带到了地球最远端， 去搜寻这片未知大陆 可能的新入口。 2009年，我有幸走访了特普伊桌山， 它位于奥里诺科河和亚马孙河流域。 看到这些山峦的第一眼就让我陶醉。 它们的四周是陡峭的石壁，垂直于地面， 银色的瀑布悬于崖上， 最后消失在丛林中。 它们用数百万年岁月沉淀的灵气， 让我感受到大自然的原始之力。 有很多作品受到这一壮丽景象的启发， 比如柯南•道尔在1912年 创作的小说《失落的世界》。 这里的的确确是一个失落的世界。 科学家们将这些山脉视为“时间的岛屿”， 它们拔地而起，高耸于周围的低地之上， 已有千万年之久。 四周的峭壁高达千米， 形成了人类无法攻破的堡垒。 实际上，只有少数的山峰被人类征服过， 探索过山顶。
5:03
这些山脉还包含一个科学悖论： 它们是由石英组成， 石英是地壳中很常见的一种矿石， 由石英组成的岩石叫石英岩， 石英岩是地球上最坚硬、 最难被溶蚀的岩石之一。 因此我们根本没想过 会在那里发现洞穴。 尽管如此，在过去十年间， 来自全球各地的洞穴学家，意大利 斯洛伐克，捷克， 当然还有委内瑞拉和巴西， 在这个区域发现了许多洞穴。 这怎么可能呢？
5:39
要理解这一矛盾， 我们必须考虑时间的因素， 因为特普伊山的历史非常悠久， 这些石英岩的形成始于16亿年前， 1亿5千万年前，随着盘古大陆的分裂， 随着大西洋形成， 这些岩石开始逐渐上升。 想象一下，水流拥有 上千万甚至上亿年的时间 来雕塑特普伊山坚硬的表面， 甚至劈开山体，形成石头城，岩中城， 还有塔林，形成了特普伊山特有的美景。 但没有人能够想象出 在如此长的岁月中， 山脉内部到底发生了什么。
6:31
于是，在2010年， 我将目光锁定在其中一座山峰， 阿岩－特普伊山，它因天使瀑布而闻名， 天使瀑布是世界最高瀑布， 垂直落差达979米。 通过（分析）卫星图像， 我寻找洞穴系统 存在的迹象， 最终我发现一个区域有地表坍塌的现象—— 也就是说，大块的、成堆的岩石—— 这表明，底下是空的。 毫无疑问，山体中间有些东西。
7:07
于是，我们数次尝试前往这一区域， 通过陆路和直升机， 这一过程非常艰难，要知道， 这些山脉终年被云雾覆盖。 风力很大， 年降水量高达4000毫米， 因此找到合适的时机 （攀登）真是非常困难。 直到2013年我们才最终抵达这一地点， 开始探索底下的洞穴。
7:39
这个洞穴非常巨大。 是一个庞大的洞穴网络， 位于特普伊高原地表以下， 在短短的十天时间里， 我们探索了超过20公里的洞穴通道。 那里地下河纵横交错， 沟渠遍布，石室众多， 还有非常深的岩井。
8:04
真是一个神奇的地方。 我们将其命名为“伊玛瓦利 耶尔塔”。 在佩蒙土著语里的意思是“众神的居所”。 要知道，土著人从未去过那里。 他们不可能抵达那个区域。 然而，当地的确有传说， 关于山中洞穴的存在。 因此，当我们开始探索时， 我们心怀敬畏之心， 不仅因为当地土著居民的宗教信仰， 还因为这确实是个神圣的地方， 因为之前从未有人类踏足过。 因此我们制定了特别的规程 避免我们的探索对环境造成污染， 同时，我们也尝试将发现成果， 与当地社会分享 。
8:50
这些洞穴能让我们一窥历史的样貌。 这些洞穴形成的时间， 长达5千万甚至1亿年， 也许是我们在地球上 能找到的最古老的洞穴。 你在那里真的能找到 失落世界存在的证据。
9:16
当你进入一个石英岩洞穴时， 你不得不将以往对洞穴的 了解都抛在脑后—— 我说的是典型的石灰岩洞穴， 或者说观光洞穴， 你在世界上很多地方都可以找到。 因为这样一个看起来普通的钟乳石， 不是是由碳酸钙组成的， 而是蛋白石， 而一个这样的钟乳石 需要上千万年的时间才能形成。 还有些形状更奇怪的， 比如这些由二氧化硅形成的蘑菇， 生长在岩石之上。 大家可以想象下， 当我们发现这些时有多激动。 我们是首次进入（这个洞穴） 和发现这些未知物体的人， 比如这些像怪兽蛋的物体。 我们有点点害怕， 因为不知道会找到什么， 我们可不想碰到恐龙。 当然，恐龙并未出现。
10:07
（笑声）
10:09
好吧，实际上，经过一些研究之后， 我们弄明白了这种结构， 我们发现这些物体是活着的有机体。 它们是细菌聚落， 使二氧化硅形成矿物结构， 就像叠层石一样。 叠层石是我们在地球上 能找到的最古老的生命形式之一。 在特普伊山地区（这个洞穴中）， 有意思的是，这些细菌聚落， 在与外界隔离的情况下完成了进化， 而且从未与人类接触过。 完全与世隔绝。 在这里可能会产生 科学上的很多新发现， 因为在这里你有可能找到 能治疗某些疾病的微生物， 或者有可能发现 具有未知特性的新材料。 事实上，我们的确在洞中 发现了一种新的矿物结构， 叫做rossiantonite， 它是一种磷硫酸矿物。
11:10
所以无论你在洞中发现了什么， 即便是一只小蟋蟀， 它也在这黑暗的与世隔绝之地完成了进化。 说真的，你在洞中所感受到的， 是生物世界和矿物世界的真实联系。 因此，当我们在探索这片黑暗的大陆时， 在不断发现它在矿物学 和生物学上的多样性和独特性时， 我们很有可能找到 地球生命起源的线索， 弄清楚生命进化 与矿物世界之间的联系。 看似漆黑一片，空无一物的环境， 有可能充满奇迹 包含许多有用的信息。
12:01
我们组建了一支由意大利、委内瑞拉 和巴西的洞穴学家组成的队伍， 名叫“La Venta Teraphosa”， 我们将很快返回拉丁美洲， 因为我们要前往亚马孙流域深处 探索其他的特普伊山。 （那里）还有很多未被探索过的山脉， 比如马拉瓦卡山，海拔将近3000米， 还有阿拉卡山，位于巴西内格罗河上游。 我们认为可以在那里 发现更大规模的洞穴系统， 而每一个洞穴里 都藏有一个未知的世界。
12:37
谢谢大家。
12:38
（掌声）
12:44
布鲁诺•吉萨尼：谢谢，弗朗西斯科。 给我们带来一个这么难忘的演讲。 弗朗西斯科，你刚才说到， 我们不用去火星寻找外星生命， 实际上，上次咱们 见面的时候，你在撒丁岛， 训练欧洲的宇航员。 作为一个洞穴学家， 你具体教宇航员什么东西呢？
13:00
弗朗西斯科•绍罗：没错，是在撒丁岛， 这项训练不仅针对欧洲宇航员， 还有来自美国、俄罗斯、 日本的航空航天机构的宇航员。 他们要在洞穴中与世隔绝地待一星期。 他们必须在十分危险的环境中开展合作， 对他们而言那就是外星环境， 因为那里非同寻常。 周围总是漆黑一片，而他们要开展科研工作， 完成各种各样的任务。 这一情况跟前往火星， 或者前往国际空间站很类似。
13:28
BG：从理论上讲（很类似）。 FS：没错。
13:29
BG：我想再看一张图片， 刚刚在你的幻灯片里出现过， 我觉得它很有代表性
13:35
这些照片都非常美？对吗？
13:38
观众：没错！
13:39
（掌声）
13:43
FS：这要感谢La Venta团队里的摄影师， 这些美丽的照片都是出自他们之手。
13:50
BG：你们的探险队伍里还有摄影师。 他们是专业人士， 既是洞穴学家，又是摄影师。 但是我在看这些照片的时候， 我在想，洞里面几乎没有任何光线， 而这些照片看起来曝光得非常好。 是怎么做到的？ 你的同事们，那些摄影师， 他们是怎么拍出来的？
14:09
FS：没错。他们基本上 像是在暗房里工作， 你可以打开相机的快门 利用光线来拍摄周围的环境。
14:16
BG：就像这样——
14:17
FS：没错。你可以将快门打开， 甚至一分钟那么久 然后拍摄周围的环境。 最后就能得到你想要的效果。
14:24
BG：你用光线来拍摄环境， 就能得到这些照片。 也许哪天我们可以在家试试。 （笑声）
14:30
BG：弗朗西斯科，谢谢。 FS：谢谢。
14:32
（掌声）
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