Powers of Ten (1977): From a Chicago Picnic to a Proton

HN commenters recommend it as the classic visualization for building intuition about scale, and it comes up whenever a thread concerns scale or size comparisons.

The Eames Office's 1977 film Powers of Ten starts at a picnic in Chicago and zooms out by a factor of ten every ten seconds to the edge of the universe. It then zooms inward to a proton in a carbon atom.