We know that Tony Stark's Iron Man suit is powerful—when fully charged, it can lift over 100 tons—but, we probably didn't realize just how heavy it is. The original suit in the first ‘Iron Man’ movie weighed over 90 lbs. That's big, hot costume to have to act in all day. And, to think, it was almost not even Robert Downey, Jr. underneath all that armor. Find out which other actors made the cut, and a lot more, in the latest invincible installment of You Think You Know Movies!