The Mysterious Hessdalen Lights of Norway
Hessdalen, Norway has been witnessing strange balls of light in the sky since the 1930s. While some sightings can be explained, others remain a mystery. One theory suggests that the phenomenon is caused by radon decaying in the atmosphere, while another proposes that the valley is acting as a natural battery. The valley is split in two by a river, with zinc and iron-rich rocks on one side and copper-rich rocks on the other, and the missing piece to support the natural battery model was identified in 2012 with the rediscovery of local sulphur mines. However, there is still no overall consensus on what is causing the lights.