This summer, when the games return to Greece for the Athens 2004 Olympics, athletes will again compete in the ancient stadiums at Olympia and Nemea.

The 100-meter races are sponsored by the Society for the Revival of the Nemean Games, founded in 1994 by the citizens of the villages of Ancient and New Nemea to revive the spirit of the ancient contest. The society’s stated hope is that ‘‘anyone and everyone’’ will participate, and contestants ranging in age from 10 to 97 have signed up to run in the 100 meters, the 7.5-kilometer ‘‘Footsteps of Herakles’’ race, or both. Then, on Aug. 18, the shot-put event in the Athens 2004 Olympics — the XXVIII International Olympiad — will take place at Olympia, bringing the games back to the place where they began.

Every four years from 776 B.C. to A.D. 394, athletes from throughout the Greek world came to Olympia to compete for a victor’s wreath of olive fronds — a prize more appropriate for a goat, as one ancient cynic remarked. For almost 200 years, Olympia held the monopoly on the Panhellenic games, but during the sixth century B.C. games were founded at three other sanctuaries: Delphi (586 B.C.), Isthmia (580 B.C.) and Nemea (573 B.C.). Of the four, Delphi in central Greece was best known both then and now for its famous oracle. By contrast, the three Panhellenic sites in the Peloponnesus — Olympia, Isthmia and Nemea — all owed their fame to their games.

Recently, I set out by car to revisit the Peloponnesian sites where most of the athletic action in ancient Greece took place. It is technically possible to leave Athens in the morning, see Isthmia and Nemea by midafternoon, pull into Olympia in the early evening and take on the imposing site, a 10-minute walk from the village, and its three excellent museums the next day. Preferring to leave endurance contests to the athletes, I spent a day at Isthmia and Nemea and two full days at Olympia.

I’ve seldom encountered any other visitors at Isthmia, or enough visitors at Nemea that I wanted to flee, but Olympia gets a steady inundation of tour groups. The best way to avoid the throngs is to arrive precisely when the site opens, leave when it becomes hard to see the monuments because of the groups, and return an hour or two before the site closes, when most visitors are long gone. Still, crowds at Olympia are hardly a new problem. The first/second century A.D. philosopher Epictetus groused: ‘‘Aren’t you crushed by the crowd? Aren’t you bothered by the noise, the din and other nuisances?’’

Olympia sprawls along a green valley in the northwest Peloponnesus, shaded by olive, pine and poplar trees, watered by the Alpheus and Kladeus Rivers. Olympia usually smells wonderful, scented by wildflowers in the spring, and oregano, thyme and the pine trees in the summer. In late antiquity, the two rivers repeatedly burst their banks, flooded and finally buried the sanctuary. It’s almost impossible to believe, but this vast site went missing for more than a thousand years. Then, in 1766, the English antiquarian Richard Chandler rediscovered Olympia, and in 1875, German excavators began to unearth the monuments.