In mid-1947, a United States Army Air Forces balloon crashed at a ranch near Roswell, New Mexico. Following wide initial interest in the crashed "flying disc", the US military stated that it was merely a conventional weather balloon. Interest subsequently waned until the late 1970s, when ufologists began promoting 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, which then engaged in a cover-up.
In the 1990s, the US military published two reports disclosing the true nature of the crashed object: a nuclear test surveillance balloon from Project Mogul. Nevertheless, the Roswell incident continues to be of interest in popular media, and conspiracy theories surrounding the event persist. Roswell has been described as "the world's most famous, most exhaustively investigated, and most thoroughly debunked UFO claim".