That was "Operation Market Garden" which was Monty's foul up. Band of Brothers covered that one as well.
Market Garden never should have happened. It was a waste of good men. Montgomery was too timid - or war-weary - to take on an offensive like that.
I enjoyed BoB because of the accuracy. I watched the old 60s flick "Battle of the Bulge" with my Grandfather (who was actually there). I asked him what he thought and his comment was "It was a fine movie, but nobody looked cold enough". BoB got that part right, at least.
I still have a picture of Grandpa posing with his XO in thigh-high snow somewhere in the Ardennes. Both of the men have huge smiles on their faces, and I've always wondered what they were grinning about.