國家地理:Survive the Sahara 走險(xiǎn)撒哈拉

For centuries, nomads and traders have made their way here. George is determined to follow in their footsteps. There is a timelessness about this place. And desert ghosts seem to haunt the hills. But that's not the wail of lost souls echoing through the cliffs. George is drawn deeper and deeper into the canyon by the sound of bellowing camels.

It's a world-class beautiful place and all the camels are communicating. You could hear their voices echoing off the walls. It's kind of like being in a, in a cathedral.

This is Gilt Arshell, a water pool visited by the ancients and a kind of grand central station for nomads and their camels. Gilters are like highway rest stops for those who travel in the desert. Here they can fill their goatskins with water, swap news and rest their animals. This wind-scoured canyon catches and holds rainfall like a barrel. Water in the desert is a rare gift and the much-trafficked reservoir is opaque with use.

They're not really going to tell you about the peril of the walk through the water that's black with the dung of 10,000 camels.

There are other reasons to watch your step when wading through these dark waters. Reasons that have teeth: there are crocodiles here, another vestige of a wetter time. Unlike their much larger cousins along the Nile, these crocs are only five feet long and at least for now, not very aggressive. George and Dan count only 6, though there may be a few more around. It's a mystery how such a small population manages to survive here.

This is very strange seeing these pre-historic creatures that are, are trapped there like there, stuck on a little desert island if you will. In the desert, the islands are the water. And they are just got trapped there by the time.

Later, in the upper reaches of the narrow canyon, George gets another surprise---cave art from thousands of years ago.

Who were these ancient people? What were their lives like? You, when you are sitting there, you know you are sitting in exactly the same place as people did three, four, five thousand years ago. You don't know what they saw at their cave, but you can see what their impressions of that world were on the walls behind you. It's kind of like a window into an ancient dream.

wail: (n.) A long, loud, high-pitched cry, as of grief or pain. 嚎啕聲

opaque: (a.) Impenetrable by light; neither transparent nor translucent. 不透光的