While the Americans were hurriedly working on a nuclear bomb, so were the Nazis. If they had succeeded, the outcome of World War II may have been quite different. The Americans used enriched uranium, but the scientists in Germany used un-enriched uranium and heavy water to reach critical mass. They manufactured heavy water at the Vemork chemical plant in occupied Norway. Taking out the plant's heavy water lab was a critical mission for the Allies. British soldiers had attempted a raid, but they had been captured and executed. The Norwegian Royal Army stepped in for another attempt, called Operation Gunnerside. It was carried out 75 years ago, on February 28, 1943.
Rather than repeating the British strategy of sending dozens of men in gliders, flying with heavy weapons and equipment (including bicycles!) to traverse the snow-covered roads, and making a direct assault at the plant’s front gates, the Norwegians would rely on an alternate strategy. They’d parachute a small group of expert skiers into the wilderness that surrounded the plant. The lightly armed skiers would then quickly ski their way to the plant, and use stealth rather than force to gain entry to the heavy water production room in order to destroy it with explosives.
Six Norwegian soldiers were dropped in to meet up with four others already on location. (The four had parachuted in weeks earlier to set up a lighted runway on a lake for the British gliders that never arrived.) On the ground, they were joined by a Norwegian spy. The 11-man group was initially slowed by severe weather conditions, but once the weather finally cleared, the men made rapid progress toward their target across the snow-covered countryside.
The skiing soldiers moved like ninjas to avoid the Germans patrolling the roads and guarding the plant. Read how they carried out their mission at Smithsonian.