This is older than the acropolis dating from the 6th century BC, built under Hippias and Hipparchos. It remained unfinished until the Emperor Hadrian completed it some 700 years later in 131 AD. The original was huge, boasting 104 columns of which only 15 remain today.
Taking over 600 years to finish, the once massive Temple of Olympian Zeus was known in Roman times as the largest temple in Greece and reportedly hosted one of the largest cult statues of antiquity. There was much competition going on in ancient times, and each state wanted to show off its ‘skyscraper’ over others (akin to the Empire State Building until 1970 and Dubai’s Burj Khalifa today).