The Great Barrier - Sandstone Plateau
Cave of Beasts
It's extraordinary to think that the moon is both evidence of what caused Earth's 23° tilt and the celestial object that helps maintain it. But the stabilisation that the moon provides isn't perfect. And the smallest of variations in the angle of tilt can have profound consequences.
Remarkable evidence for this can be found in the Egyptian desert. This is the Sahara. Hidden in this apparently lifeless landscape is proof that the Earth's tilt has changed, and in the recent past. And that change has transformed climate and history. With me is geographer Nick Drake. He's a veteran explorer of this region. We travelled through the desert for 600 km to reach our destination. This is the Gilf Kebir, the Great Barrier, a plateau over 7,00 km in length. For hundreds of years, explorers have come here in search of the lost world. A decade ago, one group succeeded.
In 2002, a couple of Italians were exploring this region when they spotted a cave. I don't think even they could have hoped for something as spectacular as of this.
The extraordinary paintings in the Cave of Beasts, are around 8000 years old, more than 3000 years older than the pyramids.
When you start to look at the figures on the wall, this seemed to be a very athletic population of people. They all seem to be running or jumping or throwing things. But you've also got wonderful pictures of antelope here, and images of giraffe. But there are some figures that are in a very strange position indeed. There is a theory, that they could be swimming.
So where did the waters that sustained those people and animals come from? A day's travel away is the Valley of Wadi Bakht. Here, there are clues that have helped to resolve this mystery. Nick Drake studies the ancient geology of the African deserts. The pattern of highly seasonal rainfall, that Nick predicted, can mean only one thing, this now barren desert, once received a monsoon. The geology of this site tells us that the rains fell in this area between 5000 and 10,000 years ago, transforming the landscape of Wadi Bakht and creating a lake.