Well, the radiation belt for one. Considering how thin the walls of the Apollo lander were, it would not even come close to protecting the astronauts from the levels of radiation that are known to be in there. Then there is the footage of the landing that was shot. When sped up by one speed, it moves at the same rate as if it were filmed right here on earth. There is other stuff, too. Damn I wish I had a copy of that documentary I saw. Not that I necessarily believe it. But it's a strong argument against the lunar landing and it's just plain fun to watch.