The tunnel setting in the film was built in the Cinecitta studio in Italy. The producer searched the United States and Europe and found that only this studio was the most suitable, because the location of the studio is not only huge and flat, and can be built above the tunnel entrance. In addition, there is a large enough reservoir and 16 water tanks for flooding. This tunnel was completed according to the construction method of a real tunnel, because there must be vehicles passing through it, and stunt scenes must be filmed. In addition to the ventilation system, there are also safety exits and additional entrances for emergencies.
In order to shoot the big explosion in the spreading tunnel, special effects staff from Industrial Light and Magic created a 1/4-sized tunnel model. Because the size is small and everything happens extremely fast, the start time of each combustible gas nozzle must be accurate to milliseconds . In addition, in order to control the sequence and speed of the explosion, the special effects crew also used a microcomputer
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