The Temple of Olympian Zeus in Athens, also known as the Olympieion, was built over several centuries starting in 174 BCE and only finally completed by Roman emperor Hadrian in 131 CE. Its unusually tall columns and ambitious layout made the temple one of the largest ever built in the ancient world.
This is a companion discussion topic for the original content at https://www.worldhistory.org/article/815/temple-of-olympian-zeus-athens/.