How to grow a glacier

In the 13th century, Genghis Khan embarked on a mission to take over Eurasia, swiftly conquering countries and drawing them into his empire. But, legend has it that there was one obstacle that even he couldn't overcome: a towering wall of ice, grown by locals across a mountain pass. M Jackson explores the ancient methods of growing glaciers and how they can be used to combat climate change. [Directed by Artrake Studio, narrated by Addison Anderson].