The Olympics (search) returned home Friday to a lavish welcome in an opening ceremony invoking Greek mythology, civilization and culture and closing an epic circle in sports: from the games' 19th-century rebirth to the latest gathering of the world's greatest athletes in an age beset by fears of terrorism and instability.

At dusk, a countdown video filled the screen at the recently upgraded Olympic Stadium — 28 seconds, one for each of the games scheduled since the first modern Olympiad in 1896 in Athens. Each tick of the clock was accompanied by the amplified sound of a human heartbeat.

Then, with a blast of fireworks around the stadium roof, the ceremony was under way. Minutes later, the five Olympic rings were ablaze in fire in the middle of a manmade "sea" in the middle of the stadium.

The extravaganza was a victory for Greek organizers, who managed to pull together the 2004 Games despite serious construction delays, worldwide skepticism and terrorist worries that pushed the security price tag to the most expensive in Olympic history and required help from NATO and other nations.

"The great moment as come!" cried the announcer in the stadium. Moments later, the parade of nations began led by Greek weightlifter Pyrros Dimas, who is seeking his fourth consecutive gold medal at the games.

A round-the-clock work blitz — under broiling sun and blinding spotlights — managed to accomplish what many had considered out of reach: pulling 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 attacks.

Earlier, an International Olympic Committee (search) member who helped oversee the preparations noted how much was at stake.

"I think you have saved Greece and saved the IOC from great humiliation," Alex Gilady told Athens organizers.

But the pride and relief of Greek organizers was tempered by a doping scandal that could threaten 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.

Greek taxpayers also are starting to tally up the worrying bill. Officials say the games will exceed $7.2 billion, and some analysts say it could hit a staggering $12 billion, including a record $1.5 billion for security.

Under a new weblike stadium canopy — finally bolted into place only last month — the modern heirs of the Olympics hoped to make the world forget the bumpy road to the opening ceremony and concentrate instead on the 16 days of competition.

Not surprisingly, Greek mythology played a central role in the extravaganza that officially began the Olympiad, a big-budget show running from reverent tradition to Las Vegas-style pageantry.

After the burning Olympic flames subsided, a boy on a replica of a ship then 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.

Spectators participated in the main ceremony by clapping and using flashlights and bells when signaled. The Icelandic singer Bjork (search) was one of the night's headliners.

The main part of the ceremony was designed to be "an allegoric journey of the evolution of human consciousness ... from the mythological perception of the world to the logical," said Dimitri Papaioannou, the concept creator of the ceremony.

The parade of nations had a distinct Athens stamp.

Greece, because of its links to the ancient games, entered first, as usual. But, as the host nation, Greek athletes also were the last into the stadium in the biggest procession in Olympic history.

Among the 10,500 athletes under 202 flags: the debut appearance of competitors from the sprinkling of Pacific atolls known as Kiribati, and the return of Afghanistan after an eight-year absence, with Afghan women for the first time. Huge cheers went up for the Afghan athletes, led by a female flagbearer — coach Nina Suratger in a shimmering green costume.

All along, Greek officials continually described the Olympics as a way to shed the country's reputation as a parochial and unruly corner of the European Union (search). The transport minister even said drivers' respect for Olympic lanes shows Greece can be "civilized."

The Olympic deadlines forced projects long taken for granted in other European capitals: highways around city centers, a serious subway and rail network and efforts to preserve architectural landmarks.

"No country has been more underrated than Greece," said the chief organizer, Gianna Angelopoulos-Dasalaki.

In the stadium, she proclaimed: "Greece is standing before you. We are ready. ... We have waited long for this moment. Olympic Games, welcome home."