After years of carping and chaos, Athens faces its first major Olympic test on Friday -- staging an opening ceremony before billions around the world.

If the Greeks succeed, then years of construction crises, budget overruns and security concerns will be forgotten.

If the show is a turn-off and the organisation a shambles, then the doom mongers will be out in force to condemn the country where the Olympics were born and revived.

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"With these Games, Athens wants to show the world a modern face," said Games supremo Gianna Angelopoulos, who has turned the shambles round in a city that had looked like a building site for years. "What we promised, we delivered," she said.

The signs have been good in the run-up to the launch with traffic running smoothly, security solid but unobtrusive and Athenians putting on a genuine smile of welcome.

But now they have to put on a real showstopper of an opening ceremony that can match the sensational start given to the Sydney Games, widely hailed as one of the best ever staged.

For the three-hour show offers the biggest free advertisement in the world -- showcase a country with abiding images that will seal Greece's place as a 21st century state no longer living on the glories of its ancient past.

What the producers call "stadium theatre" has become a powerful new art form and the omens for Athens look positive.

They are turning the stadium into a giant sea by flooding the arena. A flaming comet is to shoot into the water and light up the five Olympic rings.

LASER SHOW

Hundreds of drummers thunder out a human heartbeat rhythm that reverberates around the stadium. A boy floats across the shimmering lake in what looks like a giant paper boat.

"Welcome Home" is the cry as the Games return to their ancestral home with a spectacular laser show.

Many of the details have leaked out in the Greek press but the organisers are not perturbed -- they say they still have one major surprise up their sleeves for the show's big finish.

The Olympic movement has always feared the worst since the 1972 Games in Munich when 11 Israelis were killed by Palestinian guerrillas.

Now an even bigger shadow is being cast over the greatest sporting extravaganza on earth.

Patriot air defence missiles and thousands of surveillance cameras have been deployed in the biggest security operation in peacetime Europe to guard the first Summer Games since the September 11 attacks on the United States three years ago.

"We have done everything we possibly can -- and more," Angelopoulos said of the Games whose costs may soar to at least six billion euros ($7.34 billion). The security bill alone is one billion euros.

The organisers have promised not to turn the city into "Fortress Athens" but they face a delicate balancing act ensuring that prime targets like Israeli and American athletes can enjoy a safe Games.

But it could be doping, and not security that tarnishes Athens.

Several leading American track and field athletes will miss the Games in the aftermath of the drug scandal which rocked the sport when a previously undetectable steroid was discovered.

But Angelopoulos is exuding confidence now that Athens is finally taking centre stage as the smallest country to host an Olympics since Finland in the Fifties.

"We can't wait for the Games to begin," she said.