Lake Mývatn is the fourth largest lake in Iceland. Although it is shallow and 909 feet (277 meters) above sea level, it supports a rich ecosystem. The southern part of the lake rests on a lava flow that was emitted from the crater row Prengslaborgir 2,000 years ago. The land around the lake is marked with "pseudo craters," continually formed when water trapped beneath the earth's surface turns to steam and explodes through the layer above.

(Photograph shot on assignment for, but not published in, the National Geographic book Mountain Worlds, 1988)