Philippeion

The Philippeion (Greek: Φιλιππεῖον) in the Altis of Olympia was an Ionic circular memorial in limestone and marble, which contained chryselephantine (ivory and gold) statues of Philip's family; himself, Alexander the Great, Olympias, Amyntas III and Eurydice I. It was made by the Athenian sculptor Leochares in celebration of Philip's victory at the battle of Chaeronea (338 BC). It was the only structure inside the Altis dedicated to a human.

The temple consisted of an outer colonnade of Ionic order with 18 columns. Inside, it had nine engaged half-columns of the lavishly- designed Corinthian order. It had a diameter of 15 metres. The naos contains two windows, much like Hera II at Paestum. It had a carved marble roof which was decorated with a bronze poppy head on top.

Source: https://en.wikipedia.org/wiki/Philippeion