ATHENS, Aug 13: A spectacular opening ceremony launched the Athens Olympics on Friday, lifting spirits in the Games' ancient birthplace after the host nation was rocked by a drugs drama involving its two top sprinters.

A worldwide television audience saw Greece lift the curtain on the biggest sports show on earth, as patrolling helicopters and troops underlined the Games are guarded by the largest security operation in peacetime Europe.

International Olympic Committee President (IOC) Jacques Rogge and Greek leaders have said everything humanly possible has been done to ensure the safety and success of the Olympics - the first summer Games since the September 11, 2001 attacks.

Former US President George Bush is in Greece to join world leaders in a show of unity behind the Olympic ideal of peace. Prime Minister Tayyip Erdogan of Greece's long-time rival Turkey has said he will bring a message of global cooperation.

"I worry about security for a lot of events ... But sometimes we underestimate the ability of security forces to forestall these things," Bush, father of US President George W. Bush, told NBC television.

Athens' futuristic new, 75,000-seat Olympic Stadium was packed as darkness fell and spectators anticipated three hours of theatrics centred around an artificial lake in the arena.

Drums sounded out a heartbeat as the clock ticked down to the opening moment and then, amid torchlight and fireworks, a boy in a paper boat drifted across the make-believe Aegean Sea waving the blue-and-white Greek flag. -Reuters