What is the significance of the Olympic flame?

万众瞩目的北京奥运会圣火采集仪式在希腊古奥林匹克遗址圆满落下帷幕，并开启了在全球范围内的圣火传递活动。那么奥运圣火采集仪式究竟从何而来；整个仪式“暗藏”了什么玄机；奥运圣火为何要传递五大洲；传递过程中怎样保持其不被熄灭呢？

Greek actress Maria Nafpliotou (R), playing the role of a high priestess, kindles a pot with the Olympic flame during the Olympic Flame Lighting Ceremony in Olympia, Greece, March 24, 2008. (Xinhua Photo) 

The Olympic flame is one of the most important symbols of the Olympic Games. Lighting the flame has been an important part of every Olympic opening ceremony since it was first used in Berlin in 1936. The idea of keeping a flame lit throughout the Games was first used by the ancient Greeks in Olympia.

A few months before the opening of the Games, a ceremony is organized on the site of the original Games, the ancient sanctuary of Olympia. An actress dressed as a ceremonial priestess, in the robes of the ancient Greeks, lights the torch via the same technique used in the original Games.

She uses a parabolic mirror to focus light rays from the sun. The parabolic mirror has a curved shape. When it is held toward the sun, the curvature focuses the rays to a single point. The energy from the sun creates a great deal of heat. The priestess holds a torch in the center of the parabolic mirror, and the heat ignites the fuel in the torch, sparking a flame.

If the sun is not shining on the day of the lighting ceremony, the priestess can light the torch with a flame that was lit on a sunny day before the ceremony.

The flame is carried in a fire pot to an altar in the ancient Olympic stadium, where it is used to light the first runner's torch.

For the Winter Games, the relay actually begins at the monument to Pierre de Coubertin (the man who founded the modern Olympic games in 1896), which is located near the stadium. Read about this year's flame lighting here.

When the first torch is lit, the relay begins.

The flame is carried by relay all the way to its final destination. Although it is usually carried by runners on foot, other modes of transportation are also used. For air transportation, the flame is sheltered in a security lamp, similar to a miner's lamp. At night, the flame is kept in a special cauldron.

The highlight of the opening ceremony of the Olympics is the entrance of the Olympic flame into the stadium. The final torchbearer is always a citizen of the host country whose identity is kept secret until the last moment.

The final torchbearer does a lap around the stadium before lighting the huge cauldron with the Olympic flame. Pigeons are then released as a symbol of the peace in which the Olympic Games should take place.

The flame remains lit for the duration of the Games.