The pediments

Pictures can't really capture the impact of these; when you walk into the room with these pediments on opposite walls, it's jaw-dropping.

The eastern pediment, on top, depicts a chariot race, while the western pediment depicts a well-known battle between humans and centaurs (Apollo, in the center, is looking at the humans indicating that he's on their side.) I'm not a classicist, though I like knowing all the mythological details behind the art, but in this case, the pediments could have depicted an early version of a particulary contentious Black Friday sale and I would love them just as much.