Sites in Athens

When on your way to the Temple of Zeus in Olympia it would be wise to stop in Athens for a few nights and check out all of the history that this city has to offer.

Some good sites would be:
The Acropolis Museum
http://www.theacropolismuseum.gr/

The Propylaia which is the gate way to the acropolis

The actual Acropolis where there is the parthenon

the Temple of Athena Nike

 the Erechtheion

And on the south slope of the Acropolis is the Theater of Dionysus which is a cool site to see

Other sites not on the Acropolis would be:
North west of the Acropolis is Kerameikos

and west of the Acropolis there is the Areopagus of Athens

And if you are looking for a day trip away from Athens Cape Sounion and the Temple of Poseidon is a good choice

History
 The Acropolis is a city on a hill in Athens Greece. People come far and wide to see this site. The layout looks like this:

It consists of the Propylaia, the Parthenon, The temple of Athenia Nike as well as a couple more temples for her, The Erechtheion, The theater of Dinoysus, Rome and Augustus Alter, Oden of Herod Atticus and the Sanctuary of Zeus.

Most Important ones:
Propylaia: Is the gateway to the Acropolis. It was built during the years 438 to 432 BC.
Parthenon: Built after a war in 479 BC when the Greeks defeated the Persians.
The Temple of Athenia Nike: The temple of Athena Nike was added between 432 to 421 BC. It is small and you could easily miss it next to its brother structures.
The Erechtheion: The Erechtheion was started in about 420BC. It was built for a King (It's name sake) who was defeated by Poseidon.
The theater of Dinoysus: The place where the European theater first started.