Athens, Greece ? With the five Olympic rings ablaze in the middle of a man-made sea, the Summer Games returned to their birthplace Friday in an epic homecoming that joined the gods of ancient Greece and modern sport.

The biggest parade of nations in the games’ history began with an announcer’s cry of “Welcome back to Greece!” and culminated with a Greek windsurfing champion lighting the Olympic cauldron, which rose slowly at the end of a slender 102-foot arm to burn brightly above the stadium.

It was a moment many doubted Greek organizers could pull off, after years of worrisome delays and constant pressure to bolster the most expensive security network ever at the games.

The opening ceremony also closed an important circle in sports, from the Olympics’ innocent rebirth in 1896 to the latest gathering of the world’s greatest athletes under 202 flags in an age beset by fears of terrorism and instability.

“Greece is standing before you. We are ready. … We have waited long for this moment,” said the games’ chief organizer, Gianna Angelopoulos-Daskalaki, standing under a model of an olive tree in Olympic Stadium.

International Olympic Committee president Jacques Rogge urged athletes to “show us that sport unites by overriding national, political, religious and language barriers.”

“We need peace, we need tolerance, we need brotherhood,” he said.

At dusk, a countdown video filled the screen at the stadium — whose new weblike canopy was bolted into place only last month. The numbers clicked down from 28: one second for each of the games scheduled since the first modern Olympiad in an all-marble arena in central Athens. Each tick of the clock was accompanied by the amplified sound of a human heartbeat.

Then, with a blast of fireworks ringing the stadium roof, the ceremony was fully under way. Minutes later, the five Olympic rings, representing the five continents of the world, were ablaze.

“We did it! We did it!” chanted a group of flag-waving Greeks in the stands.

A round-the-clock work blitz — under broiling sun and blinding spotlights — managed to pull together the vast network of venues, transport links, villages and security needed for the athletes and heads of state at the first Summer Games since the Sept. 11, 2001, attacks.

The Olympic rings are shown in flames on a man-made sea during the opening ceremony. The Athens Games officially began Friday in Athens, Greece.

A sign of the security measures floated overhead — a blimp with supersensitive spyware. Outside the stadium sat symbols of the delays — dirt expanses instead of landscaped paths, idle cranes and trees planted just last week.

Earlier, an IOC member who helped oversee the preparations noted how much was at stake if the Greeks failed. “I think you have saved Greece and saved the IOC from great humiliation,” Alex Gilady told Athens organizers.

The spectacle of the opening ceremony — tradition mixed with Las Vegas-style fanfare — celebrated Greek history, culture and civilization.

After the burning Olympic flames subsided, a boy on a replica of a ship sailed into the arena, waving a small Greek flag. Then a centaur — the mythological half-man, half-horse — waded into the water and tossed a spear of light representing a javelin. From the center of the stadium rose a statue representing an ancient form from Greece’s Cyclades islands. The form broke apart to reveal other figures from Greek history.

The ancient god of love, Eros, flew above two lovers dancing and playing in the water. Then Eros hovered over a procession of figures from Greek history — from ancient vase paintings to a tribute to the Greek shepherd, Spiros Louis, who won the first Olympic marathon.

“The great moment has come!” cried the announcer. Moments later, the parade of nations began with the appearance of Greek weightlifter Pyrros Dimas, who is seeking his fourth consecutive gold medal at the games.

Behind him more than 10,500 athletes streamed into the stadium.

There was huge applause for Afghanistan on its return to Olympic competition after an eight-year absence and with its first female athletes.

The entrance of the more than 500-member U.S. team — led by basketball guard Dawn Staley — drew cheers. But some people also stood and put their thumbs down in an apparent show of displeasure for the war in Iraq. Moments later, the Iraqis entered to a roaring ovation.

The Chinese team was led by 7-foot-6 Yao Ming, who towered over even other basketball giants in the main stadium field. And Paraguay carried a banner that read “From Horror to Hope” in apparent reference to the supermarket fire that killed nearly 400 people earlier this month.

For nearly two hours, the teams filed along a black walkway into the stadium: Russians in ’20s-style white outfits, first-time Olympians from the tiny Pacific nation of Kiribati in woven grass costumes, Tajik female athletes in gold headdresses, women from Moldova in hot pink pantsuits, and men from Burundi dancing with spears.

Greece, because of its links to the ancient games, entered first, as usual. But, as the host nation, the more than 440 Greek athletes also were the last into the stadium — walking single file as the crowd chanted “Hellas, Hellas,” as the country is called in Greek.

But the Greek team had two glaring holes. A doping scandal threatens the country’s biggest track stars — 200-meter champion Kostas Kenteris and 100-meter silver medalist Katerina Thanou.

Kenteris had been considered the favorite to light the Olympic cauldron. Instead, he and Thanou were hospitalized with minor injuries following a motorcycle wreck. The accident came after the two were accused of evading a drug test, and they might miss the games.

But instead the honor went to Nikolaos Kaklamanakis, the champion from the centennial games that Greece wanted but Atlanta won. For Greeks, it was a poignant choice.