Hidden beneath billowing clouds, in China's remote south west, are perhaps the richest natural treasures in all China. Immense rivers carve their way south below towering peaks. The wind-swept slopes are home to the highest-living primates in the world and hidden in the valleys below are jungles with a diversity of wildlife comparable to those around the Amazon.

Jewel-coloured birds and ancient tribes share forests where wild elephants still roam. The mystery is that Yunnan's remote forests stretch into northern territories where deserts would normally be found. How can these northern forests exist? The rugged landscape holds the key.