The chariot arena was built by more than 1,000 workers beginning in January 1958, according to some reports. It was 2,000 feet long by 65 feet wide and covered 18 acres, the largest single set in motion picture history to that time. Reputedly, 40,000 tons of white sand was imported from Mexico for the track. [...] Because the main set for the chariot race was still being built, an identical track was constructed next to it to train horses and drivers and lay out camera shots. [...] The chariot scene alone cost about $4 million, or about a fourth of the entire budget, and took 10 weeks to shoot.
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