Mount Elgon, Uganda-Kenya Border
Clouds encircle the lofty rim of Africa's Mount Elgon, a huge, long-extinct volcano on the border between Uganda and Kenya. The solitary volcano has one of the world's largest intact calderas, a cauldron-like central depression. The caldera is about 6.5 kilometers [4 miles] across. It formed following an eruption, when the emptied magma chamber collapsed under the weight of volcanic rock above it.
Image taken by Landsat 5 on Aug. 9, 1984