Agora

This is one attraction that gets skipped, partly because it is readily confused with the Roman Agora and while you'd be falling over yourself to visit a Roman agora in Italy, well, this is Greece. But this spot offers an easy hour's wandering, with the almost-perfect temple of Hephaestus, a rebuilt colonnade housing the museum, and many minor monuments. A multiple-site combo ticket makes it a particularly good bargain to combine a visit here with the Acropolis and other nearby sites.