Salt of the EarthNorthern Ethiopia's Afar depression—also called the Danakil depression—is one of the hottest places on Earth. Parts of the region are more than 300 feet below sea level, forming a cauldron where temperatures reach above 120 degrees Fahrenheit in the summer and active volcanoes roil. (Read more about the geology of the Afar region.)The colorful and extreme Afar is also home to a valuable commodity: salt. For centuries the Afar people have mined rich salt deposits left behind from Red Sea floods in the region—most recently, 30,000 years ago. Today, workers cut slabs of salt from the earth and pack them on to camels for a days-long journey across the desert to a market town where the slabs are sold to merchants and loaded on to trucks. (Read more about the Afar people and the salt trade.)Here a man walks across a crusty landscape of sulfur and mineral salt near Dallol, a town that has been called the hottest inhabited place on Earth. (See George Steinmetz's aerial photography of the Afar Depression.)—Katia Andreassi

Photograph by Siegfried Modola, Reuters