One morning in September 1957, a private at Fort Belvoir, Virginia, was called out of his barracks with about fifteen other soldiers to look at something in the sky. With a Kodak Brownie he photographed a black ring. He said it seemed solid, not like smoke, and not shiny. Between his second and third frames it was swallowed by white smoke. The six photographs were published in 1967 as "the amazing ring-shaped UFO."
For the Air Force's Condon study, astronomer William Hartmann asked base officials about it. They told him the photos showed a smoke ring from an "atomic bomb simulation demonstration," a show often staged at the base. Hartmann estimated the ring at about 200 feet across and traced its drift back to the demonstration site.
The Condon Report listed it as positively identified. Researcher Ann Druffel later noted that no document describing the simulator itself has been found.