Olympia, on the Peloponnesian peninsula, is the origin of the Olympic Games, first held there in 776 B.C. In 2004, the Games return, this time to Athens.See Olympia Map. The ruins of Mycenae, 600 years old when the Parthenon was built, reveal the Atreus Treasury, defense walls and monumental Lion Gate from the palace of Agamemnon, Troy’s epic foe. Sparta once was the mightiest of the city-states. In Corinth, the ruins of the Agora and the Temple of Apollo are still visible.