第37期:喜马拉雅山

A vast mountain range rises up over 27,000 feet. These are the Himalayas.

And the highest mountain of all, Mount Everest. Its summit reaches up into the Earth's jet stream,

the same altitude where planes fly. When the snow on the peaks melts, it feeds rivers like the Ganges, Indus, Yellow and Yangtze.

The Himalayas are like a vast water tower. One day, their rivers will supply water for almost half the world's population.

20 million years ago, this is our planet, with every continent, and every ocean as we know it.

Except one thing is still missing, the human race. And for humans to evolve, something needs to change.