The most impressive part? They managed to tow their balls all the way up there.
This sounds like some badass Kirk Douglas movie (in fact, it is), but it's exactly what happened during Operation Gunnerside in 1943. When the Germans rudely came to crash on Norway's couch in the early '40s, they took over a factory up in Telemark that produced heavy water -- aka, exactly the thing they needed to make plutonium. The Allies, realizing that "Nazis with ingredients for an atom bomb" was a somewhat undesirable situation, sent 30 British Army officers to sabotage the plant, but a combination of awful weather conditions and the Gestapo killed the entire group. So, the Allies sent something even more deadly than 30 Brits: 11 Norwegians.
As if the mission wasn't insane enough, the Germans then decided to beef up the plant's defenses, sprinkling mines, floodlights, and guards all over the place. The only way to get into Hitler's Arctic nuke factory was a Nazi-held bridge over a 660-foot ice gorge, because sometimes history sounds like s**t that we just made up.
It looked like this, but covered in snow and swastikas.
Or at least the Germans thought that was the only way in -- the Norwegians simply climbed down the supposedly un-scalable ice gorge and snuck into the factory. They laid the explosives and were about to light the fuse and escape, but (and none of this is a joke) the base's Norwegian caretaker, whom they were holding at gunpoint, announced he'd lost his glasses and refused to leave until they were found. Naturally, the commandos put the "stop Hitler from getting the bomb" plan on hold until they'd located gramps' glasses.