Yarlung Zangbo Grand Canyon in southwest China's Tibet Autonomous Region is the largest and deepest canyon in the world. It is 504.6 kilometers long, with an average depth of 2,268 meters and a maximum depth of 6,009 meters. Many areas are still untouched in the canyon, making it a secret land. Glaciers, cliffs, steep slopes and billowing rivers crisscross the entire region, where abundant hydropower resources are stored and endangered ancient species also thrive.