# Changbai Mountain
Changbai Mountain, located on the border between China and the DPRK, is the source of the Tumen, Yalu, and Songhua rivers.
The most well-known site on the mountain is the Tianchi, or Heaven Lake. As a crater lake perched atop the mountain, locals believe that Tianchi is a holy lake.
The Changbaishan Nature Reserve was involved in UNESCO's "Man and Biosphere" program in 1980 and has become part of the world's biosphere reserves.