Area 51 has spawned more conspiracy theories than perhaps any other military facility in the world. Here’s what we know (and don’t know) about this secret U.S. military installation.

Area 51, secret U.S. Air Force military installation located at Groom Lake in southern Nevada. It is administered by Edwards Air Force Base in southern California. The installation has been the focus of numerous conspiracies involving extraterrestrial life, though its only confirmed use is as a flight testing facility.