Philippeion
Ancient Olympia Municipality, Greece · built -337
The Philippeion (ῖ) in the Altis of Olympia was a tholos made of in limestone and marble. Originally, it contained chryselephantine (ivory and gold) statues of the family of Philip II, including himself, his son Alexander the Great, one of his wives Olympias, his father Amyntas III, and his mother Eurydice I. It was made by the Athenian sculptor Leochares as a memorial celebrating Philip's victory at the battle of Chaeronea (338 BC). It was the only structure inside the Altis dedicated to human beings rather than gods.
Monument data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).