Norsk Hydro
Between 1907 and 1911 Norsk Hydro built what was at the time the world's largest hydro-electric power plant at Vemork near Rjukan, and in 1934 built an adjacent hydrogen plant. A by-product of hydrogen production via water electrolysis was heavy water. It was the later Nobel prize winner Odd Hassel who told Norsk Hydro that they were in fact producing heavy water. The Norsk Hydro was controlled by the Germans during World War II, was sabotaged twice by the Norwegian resistance movement and bombed by the allied forces.