Birger Stromsheim died this past week, age 101.
He was the last surviving member of the Norwegian ski-borne resistance team that sabotaged a heavy-water production facility at the Norsk Hydro "Vemork" hydropower plant near Tinn, Norway in February 1943. The Nazi atomic bomb program had intended to use heavy water from the plant as a moderator in their reactors.
After the raid, Stromsheim and four of his colleagues then made an epic 400-kilometer escape across Norway on skis, to the Swedish border.
Given the fact that the tide of war was already turning by 1943, it's not clear to me that the Nazis would have been able to produce a bomb before the end of the war even if the tanks holding 500 kg of heavy water at Vemork hadn't been destroyed by Birger Stromsheim and his colleagues. The Nazi atomic program wasn't prioritized appropriately and they might have run out of time before getting the first bombs ready for deployment. But ... even the possibility of the Nazis acquiring atomic bombs before the Allies did is pretty horrible to contemplate. So for that, we owe Birger Stromsheim and his fellow skiers our thanks.
There's a description of the raid at PBS here, along with an explanation of heavy water.
Here's a photo of the Vemork hydropower plant:
I'm not thrilled about linking to the source, but there's also a good obituary in the Telegraph.