The Roswell UFO incident refers to the events surrounding the crash of a military Air Force surveillance balloon at a ranch near Roswell, New Mexico in the summer of 1947 which gave rise to claims alleging the crash was of an extraterrestrial spaceship.
After an initial spike of interest in the crash, the military, wishing to conceal the true purpose of the balloon which was to detect Soviet nuclear testing, reported that the crash was merely a conventional weather balloon.
Interest in the crash subsequently waned until the late 1970s when ufologists began promulgating a variety of increasingly elaborate conspiracy theories claiming that one or more alien spacecraft had crash-landed and that the extraterrestrial occupants had been recovered by the military who then engaged in a cover-up.
In the 1990s the US military published reports disclosing the true nature of the crashed Project Mogul balloon.
Nevertheless, the Roswell incident continues to be of interest in popular media, and conspiracy theories surrounding the event persist.
Roswell has been called "the world's most famous, most exhaustively investigated, and most thoroughly debunked UFO claim".