第39期:早期人类

The random movement of two plates may have kick-started a chain of events that leads to the first humans. A man and child. A scene very much like today.

But it's one and a half million years ago. They are an early species of human called Homo Erectus.

And these are the first footprints like our own; civilizations past and present,

everyone that's ever lived, the greatest inventions,

the most brilliant ideas. Human history, in all its complexity and splendor, begins here and now.

The climate changes again. 70,000 years ago sea levels fall.

And the gap between Africa and Arabia shrinks to just eight miles. The Red Sea is now narrow and shallow enough for a small group to cross, out of Africa.

They're another later species of human, called Homo Sapiens.