In all, 2,200 computer-controlled lights and nearly 200 projectors were used to create the fantasy world of lights. And 15,000 performers with thousands of costumes, nearly 10,000 props and 14,000 pairs of earphones were used in the performance.

Chief lighting designer Cai Guoqiang said lighting the cauldron involved the meticulous co-ordination of eight elements, including quietly putting the flame tower in place as the athletes marched in and the mid-air movements of the final torch-bearer, Li Ning .

Li had to maintain his balance during his 500-metre 'run' along the top rim of the roofless 'Bird's Nest' stadium. Two sets of glide tracks {minus} one electronic and a manual backup {minus} were used for his harness.

While all eyes were on the athletes marching into the stadium, the cauldron tower was moved into place, hoisted into its vertical position and secured. Repeated test runs of the procedure were carried out in a Beijing suburb from May, and the lighting of the cauldron by Li was practised five times.

Mr Wang said it was extremely hard to synchronise the actors' performances with images - such as those in the impressive 'four great inventions' and the countdown to the giant scene created by drummers.

Beijing Traffic Management Bureau deputy director Wang Li said all 6,500 traffic police in the city plus more than 84,000 volunteers were deployed to make sure the 160,000 actors, athletes and state leaders were able to leave the stadium within 27 minutes.

No officials involved would disclose the cost of the extravaganza, repeating the oft-quoted claim that the Beijing Olympics was a 'frugal Games'.