Beijing: In a symbolic start to the games, Beijing's Olympics torch relay launched on Monday amid tight security.

Chinese President Hu Jintao lit a cauldron on a rostrum on Tiananmen Square before handing the torch to World and Olympic champion hurdler Liu Xiang.

"The century-old dream of the Chinese people to host the Olympic Games has been turned into a reality," said Xi Jinping, who is overseeing Olympic preparations.

The torch relay around the world would illustrate unity ahead of the August 8 opening of the Games. Protests have marred the event.

A second flame was lit to be taken to Tibet, where an attempt will be made to take it to the top of Mount Everest in early May.