Official Travel Guide to Norway:

Rjukan is situated deep in the narrow Vestfjord Valley in Telemark. Due to the high mountains surrounding the valley, among them The Gaustadtoppen Mountain at 1,883 metres above sea level, there is no sunlight six months of the year (from September to March).

This winter, the darkness will finally come to an end.

I live in Vancouver, BC and it can be bad enough here in the winter with all the dreary rain we get but can you imagine six months of no sun?