The Temple of Olympian Zeus is a former colossal temple at the centre Athens. It was dedicated to Olympian Zeus, a name originating from his position as head of the Olympian gods. Construction began in the 6th century BC (around 520 BC) during the rule of the Athenian tyrants, who envisaged building the greatest temple in the ancient world, but it was not completed until the reign of the Roman Emperor Hadrian in the 2nd century AD, some 638 years after the project had begun. During the Roman period the temple -that included 104 colossal columns- was renowned as the largest temple in Greece and housed one of the largest cult statues in the ancient world.
The temple's glory was short-lived, as it fell into disuse after being pillaged during a barbarian invasion in the 3rd century AD, just about a century after its completion. It was probably never repaired and was reduced to ruins thereafter. In the centuries after the fall of the Roman Empire, it was extensively quarried for building materials to supply building projects elsewhere in the city. Despite this, a substantial part of the temple remains today, notably sixteen of the original gigantic columns, and it continues to be part of a very important archaeological site of Greece.