A top-secret map keeping tracking of UFO sightings throughout the US has been revealed in the latest batch of classified files released to the public.

This is the original flying wing, the Horten 229. As BBC Future noted in 2016, the ‘flying wing’ design is not a common sight in the skies because it’s an incredibly hard concept to make work.

In the popular consciousness, disc-shaped UFOs immediately bring space aliens to mind. In reality, though, several countries have actually designed, built, and flown “flying saucers,” including some ...