It was once the heart of the Mayan civilization that ...
stretched across Central America, a great city known as Tikal.
It's temples were the tallest in the Western world ...
monuments to it's kings and architects.
For centuries, Tikal grew larger, it's science and arts flourished.
Then, a thousand years ago, at the height of its power,
the city was suddenly abandoned.
What happened in this lost world?
What keeps all cities, all civilizations alive ... then and now?
Cities like New York are triumphs of human technology ...
they feel as if they will last forever.
And they give us the sense that we're somehow apart from the rest of nature.
In big cities, it's easy to take a lot of things for granted:
Food comes from the supermarket, water comes from the faucet,
or does it?
Eight million New Yorkers drink clean water from the Catskill mountains,
a hundred miles away.
If New York had to build water purification plants,
it would cost billions.
Here, nature provides that service, free of charge.
If we could follow the rainfall down through the leaf litter,
we'd find that what we think of as dirt is a world teeming with life,
a metropolis much more densely populated than the city it serves.
In every square inch, billions of microbes ...
and other organisms, go about their business,
building and enriching the soil we grow our food in ...
helping condition the air we breathe ...
and cleaning the rainwater on its way downhill to the reservoirs.
It's just one example of what scientists call biological diversity ...
the variety of interconnecting life that keeps things healthy all over the planet.
Everywhere, nature has found ways to thrive.
Each place, each ecosystem shapes its own community of plants and animals.
In every ecosystem, there is a balance of relationships that keeps it working.
The giant seaweed called kelp,
is many things to many creatures. It's a hiding place —
It's a nursery for spawning fish —
and it's a food supply for the sea urchin,
a spiny creature with a big appetite.
If there are too many of them,
urchins can virtually clear-cut the underwater forest.
Until the 1970s, this was happening along the California coast,
all because an animal that belongs here was missing —
an animal that loves to eat urchins - the sea otter.
It had been hunted almost to extinction for its thick coat of fur.
Then, people decided to protect the sea otter, by law,
and their numbers grew.
The balance of life began to re-establish itself.
Now, wherever there are otters,
the kelp forest flourishes and so does everything in it.
In the tropical forest, biological diversity reaches its peak.
There are countless opportunities and life seems to seize them all.
Like the kelp forest, the health of the rain forest is maintained by the ...
variety of its inhabitants as long as the natural balance is undisturbed.
Animals can't live without the habitats they're adapted to.
Many, like the South American Tapir,
are now threatened or endangered because they're losing the places they live.
The forests are shrinking.
For thousands of years, more than one third of Earth's land mass ...
was covered with pristine forests, full of life.
The forests of China and lands around the Mediterranean ...
were first to be cut as towns became cities and nations.
The rate of loss speeded up with the Industrial Revolution.
But in the last 50 years, we've cleared more forest than in our previous history.
Less than half is left.
Scientists estimate that thousands of species of animals, plants, insects,
and other organisms are being driven to extinction each year,
with unknown consequences.
We are changing the world to quickly for animals to be able to change with it.
In major institutions around the world, scientists are now working against time,
to find and understand all the diversity of life that remains.
Nearly two million species from Beetles to Blue Whales,
have been classified,
but there could be ten times that many, still undiscovered.
The priority now is to explore the places with the most unique biodiversity ...
where the web of life is still intact.
Fabian Michelangeli of the American Museum of Natural History is going ...
back to his native Venezuela, to join a Rapid Assessment Team on an expedition ...
to the fabled Lost World, that inspired the novel by Sir Arthur Conan Doyle.
I don't think we'll find a dinosaur on this trip, but in all of South America,
there's no place more incredible than the Table Mountains of Southern Venezuela.
The expedition is being organized in the capital of Venezuela - Caracas.
Leader of the Rapid Assessment Team is biologist Margarita Lampo,
whose specialty is amphibians.
I always had a passion for animals, ever since I was a little kid.
I liked the idea that everything in nature was connected to something else.
For ten years, I've been studying frogs and toads.
These creatures can tell us so much about the health of the places where they live.
My colleague Celsi Senaris and l are concerned by evidence ...
that frog populations are declining all over the world.
Now we have the chance to search for them ...
in a place were few people have ever been.
For the next few weeks, we'll be living in very different conditions.
We are heading southeast towards Canaima.
The plan is to meet our guide at the airstrip, go up river by canoe,
and hopefully, by helicopter to the top of Mount Roraima.
Beneath us is the vast watershed of the great Orinoco River.
Tonight we'll stay in a Pemon Indian village where we've hired a local boatman.
The Table Mountains are a lot closer now.
I like the Pemon word for them "Tepuy".
But I can see why others have called them the Lost World.
Now it's too shallow for the boat.
We'll hike from here to the helicopter and explore the rainforest on the way.
I can't believe the beauty of this place.
On the riverbank, we found some fresh tracks.
Only hours ago, a Jaguar was here.
This tells us that the ecosystem still has a full range of biodiversity.
Large predators control the number of mammals like the Coatimundi,
so they don't overgraze the fruits and seedlings, or eat too many birds eggs.
This balance helps to ensure the health of the forest.
Now, this is it - the moment I've been thinking about for weeks.
Our guide Nadim, says these pilots know the mountains better then anyone.
Next stop, the summit of Mount Roraima.
Mount Roraima is a biological island lost in time,
eroded by eons of wind and rain.
The pilots don't want to shut off the engine up here.
The weather changes too fast.
They have to get out before the next storm,
and one is coming in fast now.
They'll be back with supplies in three days ... if they can.
I had mixed feelings watching the helicopter leave.
It was like being left alone on another planet,
surrounded by images from the dawn of time.
In these conditions, shelter is the priority.
Science will have to wait.
Roraima is a natural laboratory for studying ...
the adaptation of species to harsh environments.
Fabian is the team's plant specialist.
All over Roraima, there are these beautiful miniature gardens.
Most of the summit is bare rock, so the rain runs off quickly.
Plants only grow in depressions where water and soil can accumulate.
If we carefully examine these little islands,
we see that they are lying just like rugs on top of the rock.
The soil is mostly sand, with very few nutrients.
But it still supports an incredible amount of life,
probably half of it exists only on these mountains, and no where else.
In this nutrient-poor environment,
plants have evolved different strategies for survival.
Some have become carnivorous, trapping and consuming insects.
Other carnivorous plants lure insects with vivid color and attractive scent.
And their pitcher-shape is also a perfect trap.
Thousands of slippery hairs cover the inside of the pitcher.
It's only a matter of time before the victim slips into the bowl of rainwater ...
where larvae and other organisms break down the insect.
The plant absorbs the nutrients in the water.
Roraima seems like a great place for amphibians,
with ponds and streams everywhere.
But at first we saw nothing at all.
And our samples showed that the water is as poor a food source as the soil.
Any creatures living here have to be very resourceful.
Then we found our first amphibians;
Tadpoles feeding on clusters of unhatched eggs.
The mother frog apparently produced extra eggs,
so her offspring would have plenty to eat!
Nearby, we saw a frog laying eggs in a plant,
the only carnivorous bromeliad known to science.
The water below is full of captured insects.
Once her eggs hatch, the Tadpoles can make a feast of the soup ...
and maybe the plant gets something too like nitrogen from their waste products.
At dusk, we heard a sound we never heard before ...
definitely amphibian, but strange.
We looked for it, until the sound stopped.
In the morning we heard it again.
Celsi recorded the sound, but we never saw the creature that made it.
Later we did come across something truly unique —
a tiny black toad, threatened by a Tarantula.
It didn't jump, it just walked away and climbed the rock.
When the Tarantula moved on, the toad curled itself up and rolled down again.
Now, that I've never seen before!
Why would nature produce a tiny toad that walks and rolls instead of jumping?
No doubt, we still have a lot to learn ...
People often ask me why we should care about creatures like this.
Well, it may have something we need, like new medicine or chemicals,
or maybe because it's living proof of nature's ability ...
to diversify and survive ...
in ways we never even imagined.
It's a long way from the Lost World of Venezuela to the suburbs of New York,
but the diversity of life here is just as fragile and just as important.
Like the life of remote rain forests and mountains,
the creatures in our backyard all play their part in the ...
balance of relationships that keeps the world healthy.
Insects need flowers, flowers need insects ...
and we need the food that pollination produces.
In just one square meter, young explorers on a field trip can find a lot of life.
If they look hard enough, they'll find things even scientists haven't seen before.
We all need to know what lives here what it does and what it means to us.
But as we take up more and more space on the Earth,
we may tip the balance of life without even knowing it.
It wouldn't be the first time.
The lost city of Tikal was discovered just over a century ago,
buried in the tropical forest of Guatemala.
Experts still debate what happened to this metropolis of kings and priests,
warriors and farmers where the rare black Jaguar,
sacred to the Mayans, can sometimes be seen at dawn.
New studies suggest that, if we could imagine Tikal as it was,
we might see that its expanding population had stripped away the forest ...
for miles around, exhausted the soil, water, and food supply ...
with famine, warfare and collapse not far behind.
Over a thousand years the forest has returned ...
but the high civilization of the Mayans is no more.
Did the people of Tikal lose their life support system ...
without ever understanding it?
Surrounded by the marvels of a modern city,
we believe we are masters of our destiny.
But everything in our homes, everything that keeps us alive, comes from nature.
A hundred years ago, the people of New York ...
had the foresight to preserve a critical part of its life support system ...
the mountain forests and soil that clean its drinking water.
Thirty years ago, the marine ecosystem off the California coast began ...
to restore it self, because we had the wisdom to protect the Sea otter.
When we protect nature, we protect ourselves.
After a week on Roraima, soaked by the rain,
we've flown to another "Tepuy" for a few days work.
We'll be on our way home soon.
But in a sense, this is our home.
The air is fresh and the waters flow endlessly.
These places give us life and remind us that we are just a small part of nature.
Frogs seems to be a kind of bellweather for the health of the planet.
If so, things are okay up here.
Will it stay this way?
I'd like to think that places like this to be here for my children.
Maybe our work will help us to understand the world we have ...
and the world we have to lose.
What could be more inspiring than to begin the age of restoration,