The Nazis never got close to building the bomb, but they understood the science and knew what was coming. A top-secret raid led by Norwegian resistance fighter Roachim Ronneberg destroyed a heavy water-producing plant in Rjukan, Telemark in 1943—a key victory that put Nazi nuke research to bed. Ronneberg died this week at 99. The following year, Ronneberg chose a team of five other commandos in an Allied operation codenamed Gunnerside. "We were a gang of friends doing a job together," he told the BBC during the 70th anniversary of the mission. The men parachuted on to a plateau, skied across country, descended into a ravine and crossed an icy river before using the railway line to get into the plant and set their explosives. "We very often thought that this was a one way trip," he said. After the explosion, the men escaped into neighbouring Sweden by skiing 320km (200 miles) across Telemark - despite being chased by some 3,000 German soldiers. With a wry smile, Ronneberg described it as "the best skiing weekend I ever had". Ronneberg told a BBC interviewer that he only realised the importance of the mission after the bomb on Hiroshima.