National Monument, northeastern Alabama, U.S. Located south of the Alabama-Tennessee border, the monument constitutes part of a cavern that was discovered с 1953.
The cave is about 210 ft (64 m) long, 107 ft (33 m) wide, and 26 ft (8 m) high. It contains an almost continuous record of human habitation dating to at least 7000 BC. The national monument was established in 1961.