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.