Established in 1924, Craters of the Moon National Monument celebrated its 75th birthday in 1999. The area is managed cooperatively by the National Park Service and the Bureau of Land Management(BLM). The Monument is a geologic wonder cast in a wild and remote landscape. Its central focus is the Great Rift, a 62-mile long crack in the earth's crust. The Great Rift is the source of a remarkably preserved volcanic landscape with an array of exceptional features. Craters, cinder coves, lava tubes, deep cracks, and vast lava fields form a strangely beautiful volcanic sea on central Idaho's Snake River Plain.