The Hessdalen lights
The account
A valley where spacecraft appear so often that it has become an observation post for visitors from other worlds.
What investigators found
The lights are real and have been recorded by cameras and radar. The cause is still being studied, with hypotheses involving dust, gases and electricity in the air.
The story
In late 1981, residents of the Hessdalen valley, in central Norway, began seeing strange lights almost every week: white, yellow or red balls that hovered, shot upward or stayed still for up to an hour.
In 1983, researchers launched Project Hessdalen, and since 1998 an automated station has monitored the valley with cameras and other instruments. The lights have been filmed and measured many times, which makes the phenomenon a fact. What produces them is still a scientific mystery, with theories involving dust containing local minerals, gases and atmospheric electricity.