What's the greatest knock-down, drag-out fight scene of all time?S

The greatest science fiction and fantasy movies inspire us to believe that we are destined for greatness, in our starships and our castles. But sometimes, you run into a problem that can only be solved with a smackdown. What's your favorite fight scene from science fiction or fantasy?

Please include a picture or clip of your chosen brawl, so we can judge it on its aesthetic merits. Thank you!

Top image: They Live.