The Parthenon is a former temple on the Athenian Acropolis dedicated to the goddess Athena. Completed in 438 BC, it is considered the zenith of the Doric order and a symbol of Ancient Greece, democracy, and Western civilization. The building is renowned for its subtle optical corrections, known as 'entasis.' For example, the columns lean slightly inward and the floor is slightly convex; if the lines were perfectly straight, they would appear to sag or lean outward to the human eye. The temple originally housed a massive chryselephantine (gold and ivory) statue of Athena Parthenos. Over the centuries, the Parthenon served as a treasury, a Christian church, and an Islamic mosque, before being severely damaged in 1687 when a Venetian mortar hit an Ottoman ammunition dump stored inside the temple.