These lights are unexplained and have been seen in the Hessdalen valley over the city of Holtålen in Sør-Trøndelag county, in Norway. The Hessdalen lights usually appear as bright white or yellow and remain static or floating just above ground level. They sometimes remain in view for over an hour. They are just one kind of unexplained light that has been observed in that particular valley. These types of lights have been reported there since before the 1940s. The lights appeared quite often from between December 1981 until the summer of 1984, when they lights were witnessed sometimes 15-20 times a week. The appearance of the lights caused an increase in tourism with visitors staying overnight to catch a glimpse of the weird light show.

After 1984, the light activity decreased and might be seen between 10-20 times a year. Scientists have some possible theories but nothing concrete. Some researchers think a possible explanation might involve some sort of plasma that lights up when it ionizes to form a cloud of ions and electrons, but it is all conjecture at this point. After all these years, they still really just don’t know.