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The Olympiad returned to its birthplace under the heaviest-ever security for a sporting event as the 28th Olympic Games started its opening ceremony Friday night (Aug. 13).

After 108 years away from its ancient birthplace and the city of their revival, the Olympics returned home at last. This time, 10,500 athletes from a record entry of 202 countries and regions are competing and 4 billion people tuned in the live broadcast of the opening ceremony.

Gone was the question mark hanging on the ability of this nation of 10 million people to host the Olympics, and everything were in place at the very last moment.

The Olympics, which runs through to August 29, has 301 gold medals up for grabs. The United States and Russia are widely predicted to finish 1-2 overall while China is to slug it out with Germany for third place.

Swimming is set to upstage athletics as American phenom Michael Phelps is all out to level or break countryman Mark Spitz's seven-gold-in-one-games record while dueling with Australian Ian Thorpe for the best swimmer billing.

The Athens Games will go down in history as the heaviest-guarded one, with a 1.2 billion euros (US$1.5 billion) Olympic security package of about 70,000 personnel and a massive array of surveillance equipment, including a sensor-laden blimp, undersea sensors and street cameras that have already annoyed the Athens populace.

As Greek taxpayers started to worry about the long bill, Olympic chief Jacques Rogge ensured that the Olympics would not lose money.

Greece's spending on the Olympic Games may rise to seven billion euros (US$ 8.4 billion), 2.4 billion over the original estimate of 4.6, widening a budget deficit that already exceeds European Union limits.

Yet the IOC president Rogge said he was confident the Greeks would stay out of the red because since 1984 the Olympics has been in profit.

A drug-free Olympics remains a Utopian dream as doping has already reared its ugly head in this Games. Kenyan boxer David Munyasia had been sent home after testing positive for the stimulant cathine while a dozen cheats had been caught when they were about to leave for Athens.

Greek pride was badly hurt when their two most famous athletes face expulsion from the Games for missing a mandatory doping test, which is treated as a failed test according to the IOC's zero-tolerance policy.

Reigning Olympic 200 meters champion Kostadinos Kenteris, who had been tipped to light the Olympic flame in the opening ceremony, and fellow sprinting medallist Katerina Thanou were injured in a motorcycle crash shortly after missing drug tests.

A Greek Olympic Committee source said the duo, ordered to appear at a disciplinary hearing next Monday, might pull out of the Olympics to save their skins for the time being.

Facts of Athens Olympic Games opening ceremony

The Olympic Stadium where the opening ceremony was held was built in 1982 and completely renovated from 2000 to 2004, with a capacity of 72,000. The new roof of the stadium, designed by Spaniard architect Santiago Calatrava, weighs 18,700 tonnes and covers a total area of 25,000 square meters.

The main performance area of the opening ceremony is filled 2162 cubic meters or 2,162,000 liters of water and this expanse of water covers an area of 9645 square meters. It takes six hours to fill the space but takes only three minutes to drain with ten drainage valves, which can empty 3000 liters of water per second. When drained from the arena, the water is stored in a circular "doughnut" reservoir that forms a ring around the pit 41 meters in diameter with a capacity of 2,300,000 liters of water.

Thirty six and half meters above the stadium is a cable net or aerial flying system, which used 37km of steel wire rope. In the cable net, there are 24 independent trajectories along which scenery can travel; each radiating outwards from a single hub set above the center of the space. 72 computer-controlled steel wire winches mounted on 18 platforms move the various scenic elements around the space and the winches control 72 cables, which together can lift 22,500 kilograms of scenery.

Editor: Catherine