1965 classic based on true WWII story about Norwegian special forces stopping the Nazis from developing the A bomb.
Richard Harris, Kirk Douglas... and hot chicks too. enough guns and skiing to make Ullr proud, cool scenery and a great story.

Catch it when you have time.

Is this the one where they blow up the heavy water plant?

Yes, or at least made the attempt. I've read the account from one of the specops guys( Skis Against The Atom by Knut Hahkalid (?)) who was involved in the raids and the movie followed fairly close.

633 Squadron is a good one too.
Same subject but with lots of Mosquito bomber footage.

yea i saw this this winter. it was better than i thought it would be i always passed over it before