Hessdalen Lights

One of the strangest UFO phenomena we have seen around the world is located in the Hessdalen valley in Norway. People in the valley have reported strange balls and streaks of light in the sky since at least the 1930s, supposedly coming from random, unrelated spots in the valley, but no one has ever been able to determine their true origins. It is a phenomenon of light that first appeared in the Norwegian Hessdalen Valley skies in the 1980s. Light disks of enormous size and various colors are what illuminate the entire valley by flying throughout the Hessdalen sky.

Some people believe that the whole affair might be explained by simply having lousy weather, rather than by UFOs or anything else definite. Or, more precisely, they are "exemplary of aberrant atmospheric luminous phenomena that occur often at various locations on Earth," as one research puts it. That still doesn't explain what's causing them, even though it may be accurate and we lack the scientific authority to dispute it.

• Year: 1980s