Erechtheion

http://www.sonic.net/~hellenik/erechtheion.html

The Erechtheion was built in replacement of the ancient temple of Athena.   It was started during the Peace of Nikias in 421 B.C., but work on it seems to have been interrupted after the resumption of hostilities between Athens and Sparta, and was finally completed in 406 B.C.   It was built on the Acropolis to honor the location that Athena was said to have made a sacred olive tree spring up during a contest with Poseidon over which one of them would claim Athens as their city.