When a massive international war-games exercise known as Operation Mainbrace convened in the North Sea in 1952, it brought together 80,000 military personnel, 1,000 planes and 200 ships from nine countries. There were also some unexpected attendees: UFOs.
Multiple sightings of unidentified flying objects (UFOs) during Operation Mainbrace (also known as Exercise Mainbrace) were documented by pilots and naval officers and appeared on radar, according to the National Investigations Committee on Aerial Phenomena (NICAP), a federal agency that compiled witness accounts of UFO encounters from the 1950s through the 1980s.
