Rjukan

Rjukan is a city in Norway. It is in the county of Telemark. The town had 3,386 people living there in January 2007. 
Between September and March, Rjukan is in the shadow of the mountains and does not get sunlight. 
Geology.
The city lies in a narrow valley.
History.
Rjukan became a city in 1996.
In 2013, large mirrors were placed on the mountainside to reflect the sun into the town square.