The Lights over Exercise Mainbrace
During NATO's largest naval exercise of 1952, crews reported silver discs and glowing objects shadowing the fleet.
What was reported
In September 1952 NATO held Exercise Mainbrace, a huge naval exercise in the North Sea and the waters around Denmark and Norway, involving more than 200 ships. During it, several sightings were reported, including a silver, spherical object photographed from an American aircraft carrier.
Airmen at an RAF base in Yorkshire also reported a silvery disc that seemed to follow one of their jets before moving away at high speed.
Explanations offered
Some sightings may have been weather balloons or aircraft; sceptics suggested the photographed sphere was a balloon released from a nearby ship. Others were never explained. The incidents helped persuade the British government to take UFO reports more seriously, and its files have since been released.
- When
- September 1952
- Where
- North Sea
- Witnesses
- Naval crews and airmen during a NATO exercise
- Status
- Unidentified
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.