A 1942 view of Bingham Canyon Mine, an open-pit mining operation southwest of Salt Lake City, Utah, in the United States. The mine has been in production since 1906 and has resulted in the creation of a pit over 0.75 mile (1.2 km) deep, 2.5 miles (4 km) wide, and covering 1,900 acres (7.7 km²), which is the world's largest man-made excavation. Bingham Canyon has proven to be one of the world's most productive mines. The value of the resources extracted, including copper, gold, silver and molybdenum, is greater than the Comstock Lode, Klondike, and California Gold Rush combined.Photo credit: Andreas Feininger