A local Chinese newspaper, The Beijing Times, revealed some of the staggering fireworks at the opening of the Beijing Olympics were actually not fireworks, but computer graphics. According the the newspaper a 55-second sequence, which included a series of 28 giant footsteps made by fireworks, was created by a visual effects team.
One could argue this was a wise decision: unlike real fireworks visual effects don't pollute the already smoggy Beijing atmosphere any further. However, confusingly the sequence of 28 footprints actually took place in the real ceremony. The organisers decided to fake the sequence because it would not 'be accurately captured' live.
To emulate the shot, the visual effects team even spoke to the Beijing meteorological office to ask them how to recreate the Beijing smog.