Rjukan was formerly a significant industrial centre in Telemark, and the town was established between 1905 and 1916, when Norsk Hydro started saltpetre (fertilizer) production there. Rjukan was chosen because Rjukan Falls, a 104-metre waterfall, provided easy means of generating large quantities of electricity. The man with the idea to use the Rjukan falls was Sam Eyde, the founder of Hydro.