THE ALTIS was the sacred enclosure ('sanctuary'), which contained:

• Temple of Hera (Heraion), built at the end of the Seventh Century, by the inhabitants of Scillous in Elaia. The visible remains are of the third temple on the same site. Among the treasures are (a) the HERMES of Praxiteles (? IV cent.); and (b) the chest of Cypselus (VI century), a gift of Corinth.
  
  
• The Pelopeion (surrounded by a pentagonal wall), a mound consecreated to PELOPS by the Achaeans of Pisa; it is perhaps the oldest monument in the Altis. In the center of the enclosure were an alter, dedicated to the Hero; his statue; and a ditch, into which black rams were sacrificed (an indication of an underworld [chthonic] cult).
  
  
• The TEMPLE OF ZEUS, built between 468 and 457 B.C., by the architect Libo of Elis, and paid for out of the spoils taken by the Eleans from the Pisans in 468. The inner chamber contained the Olympian Zeus made by Pheidias, a gold-and-ivory ('chryselephantine') statue, some 40-45 feet high, depicting a seated Zeus, holding a statue of the goddess Victory (NIKE) in his hand. The statue was made between 456 and 447 B.C., before the Athena Parthenos in Athens. The entire statue of Zeus was removed to Constantinople by Emperor Theodosius II, where it was destroyed by fire in 476 A.D.
  
  In the vestibule of the temple was a statue of IPHITOS, crowned by 'The Truce'.

On the north side of the Altis, just east of the Heraion, were the Treasuries of various cities:

1. SICYON (Achaean), originally built (according to Pausanias, who visited Olympia in 174 A.D., and left a complete account) in 648 B.C., but the remains are ca. 480-470. Here were stored the trophies of MYRON and the sword of PELOPS.
2. Disappeared before Pausanias' time; builders unknown.
3. Disappeared before Pausanias' time; builders unknown.
4. EPIDAMNOS (Dyrrachium), a colony of Corinth), contained statuary in cedar by the VI. century Spartan Theokles ('Atlas').
5. SYRACUSE (built after 480, from the spoils of the Battle of Himera against Carthage), contained three linen breastplates dedicated by Gelon the Tyrant.
6. BYZANTIUM
7. SYBARIS (the city was destroyed in 510 B.C.)
8. CYRENE (a colony of Thera and Sparta ), in which were kept statues of Roman Kings Built ca. 550?
9. SELINUS in Sicily (second half of the sixth century B. C. )
10. METAPONTUM in Magna Graecia (south Italy), once held 132 silver cups and 3 gold cups, 3 silver wine jugs.
11. MEGARA (a Doric town, between Corinth and Athens) second half of the sixth century.
12. GELA (built ca. 540); the terracottas were imported from Sicily.

In front of the Treasuries, on the path to the Station entrance, were the ZANES (statues of Zeus) paid for by violators of the integrity of the games (EUPOLUS, 338) etc.

• THE GYMNASIUM, composed of a large open field and two porticos (xyste) connected by a ceremonial entrance gate (propylon). The East Portico is exactly as long as the distance to be covered in the stadion race, and apparently one could run the race in this portico out of the reach of the elements. On the wall of the portico was inscribed the List of the Olympic Victors. The buildings are hellenistic (that is, after ca. 330 B.C.) and the propylon is of the second or first century B.C.
  
  
• The PALAESTRA (late third century B.C.): is immediately to the south of the Gymnasium, and was used for practice by wrestlers and boxers. It consisted of a central courtyard; and rooms surrounding the courtyard on all four sides, mostly entirely open to the courtyard (exedrae). Among these rooms were (a) The Ephebeum; (b) the Eleothesium (anointing room); (c) the Konisterion (a room where the athletes were rubbed down with sand); and some rooms for bathing.
  
  
• The LEONIDAION (third century B.C.), named after the builder, Leonidas: the largest building at Olympia, a guest-house for distinguished visitors. It stands opposite the south-west corner of the Altis.
  
  
• The BOULEUTERION (sixth century B.C.):('Council House'), sixth century B.C., contained the enclosure of Zeus Horkios ('zeus of the Oath'), where athletes took the Olympic Oath in the presence of the Hellanodikai.
  
  
• The HELLANODIKEION (fifth century B.C.?) was the residence of the Hellanodikai, the commissioners of the festival. It stood at the southeast corner of the Altis, opposite the Propyleion of the Altis. Just to the north of this building, facing the Altis, was the Echo Stoa, at the north edge of which was the entrance to the stadium, and at the south edge of which was the entrance to the Hippodrome
  
  
• The STADIUM. The starting line was at the east end, the finish line at the west. Total distance: one stadion, 210.5 meters, 600 feet. The stadium in the Hellenistic period could seat 20,000 spectators. There was an Official Box on the south side, opposite the shrine of Demeter Chamyne.
  
  
• The HIPPODROME, chariot racing stadium, at the south-east edge of the sacred area, is almost entirely eroded by the Alpheios River.