Bogda Mountains, China
The Turpan Depression, nestled at the foot of the Bogda Mountains in northwestern China, is a strange mix of salt lakes and sand dunes. At the bottom of the basin is Aydingkol Lake, which appears blue in this Landsat 7 image from 1999. Once a permanent lake and now a salty swamp, the lake is 155 meters below sea level, making it the third lowest place on Earth’s land surface after the Dead Sea and Africa’s Lake Assal. A region of temperature extremes, the Turpan Depression extends over 50,000 square kilometers. The city of Turpan, located in the higher northern part of the depression, was an important trading center on the ancient Silk Road.