10 Mysterious Photos That Nobody Can Explain
6. Hessdalen Lights
Strange light phenomena has been reported at the Hessdalen Valley in Norway since the 1940s, multicoloured illuminations standing or floating about ground level.
The lights have been a big hit with tourists in Scandinavia, especially between 1981 and 1984 when activity was at its peak. During this three-year period, the spectacle occurred more than 20 times per week.
Since then, the phenomena has generally occurred between 10 and 20 times a year, and has been photographed by countless onlookers.
Despite the masses of pictorial evidence, scientists and researchers have failed to settle on an unequivocal explanation for the illuminations. Some believe it's caused by a cloud of ions and electrons, but further study is needed.