UFO 'invasion' of NATO war games revealed in 'Project Blue Book' season finale

Multiple unidentified sightings interrupted the NATO exercise at sea.

UFOlogist Dr. J. Allen Hynek (Aidan Gillen) ponders a UFO sighting during NATO war games, in the Season 2 finale of "Project Blue Book."
UFOlogist Dr. J. Allen Hynek (Aidan Gillen) ponders a UFO sighting during NATO war games, in the Season 2 finale of "Project Blue Book."
(Image credit: Photo by Liane Hentscher/Copyright 2020 HISTORY)

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. 

OFFER: Save at least 53% with our latest magazine deal!

OFFER: Save at least 53% with our latest magazine deal!

With impressive cutaway illustrations that show how things function, and mindblowing photography of the world’s most inspiring spectacles, How It Works represents the pinnacle of engaging, factual fun for a mainstream audience keen to keep up with the latest tech and the most impressive phenomena on the planet and beyond. Written and presented in a style that makes even the most complex subjects interesting and easy to understand, How It Works is enjoyed by readers of all ages.

Mindy Weisberger
Live Science Contributor

Mindy Weisberger is a science journalist and author of "Rise of the Zombie Bugs: The Surprising Science of Parasitic Mind-Control" (Hopkins Press). She formerly edited for Scholastic and was a channel editor and senior writer for Live Science. She has reported on general science, covering climate change, paleontology, biology and space. Mindy studied film at Columbia University; prior to LS, she produced, wrote and directed media for the American Museum of Natural History in NYC. Her videos about dinosaurs, astrophysics, biodiversity and evolution appear in museums and science centers worldwide, earning awards such as the CINE Golden Eagle and the Communicator Award of Excellence. Her writing has also appeared in Scientific American, The Washington Post, How It Works Magazine and CNN.