Probably the second most famous building on the Acropolis is the Erectheion, built between 420-406 BCE, and built to house religious rituals.
Its plan is complicated by the fact that it was designed to accommodate the very uneven terrain,
The site drops off dramatically on the side opposite this picture.
The plan also had to avoid destroying existing sacred shrines such as the place where
Poseidon struck the Acropolis with his trident, and the sacred olive tree of Athena.

The elegance Ionic forms of the Erechtheion contrasts with the Parthenon's strong Doric style.
The Erechtheion faces east with the entrance faced with Ionic columns.
On the North and West, the temple's site drops off sharply.

The Erechtheion has two porches, one with tall Ionic columns, as well as the very famous "Porch of the Maidens",
whose columns are six massive female statues, the famous Caryatids shown in the next images.