Olympia lies in the valley of the Alfeiós River in the western part of the Peloponnese, today around 18 km away from the Ionian Sea but perhaps, in antiquity, half that distance. The Altis, as the sanctuary as was originally known, was an irregular quadrangular area more than 180 meters on each side and walled except to the North where it was bounded by the Mount Kronos. It consisted of a somewhat disordered arrangement of buildings, the most important of which are the Temple of Hera, the Temple of Zeus, the Pelopion and the area of the great altar of Zeus, where the largest sacrifices were made. The name Altis was derived from a corruption of the Elean word also meaning “the grove” because the area was wooded, olive and plane trees in particular.
Uninhabited throughout the year, when the games were held the site became over congested. There were no permanent living structures for spectators, who, rich or poor, made do with tents. Ancient visitors recall being plagued by summer heat and flies; such a problem that sacrifices were made to Zeus Averter of Flies. The site’s water supply and sanitation were finally improved after nearly a thousand years, by the mid-second century AD.