Factual error: The Liberty Bell is depicted ringing as the Declaration of Independence is being signed on July 4 (a mistake itself) in the film. The bell actually did not ring on that date, but on July 8, when the Declaration had been returned from the printer and unveiled to the public.
Visible crew/equipment: Towards the end of the film, when a tree branch damages the straw roof of the raft as it passes under a tree, you can see a crew member stood watching filming behind Aguirre and his men who are trying to dislodge the branch. He's wearing a cap, a white shirt and blue pants. (01:22:12)