Steven Spielberg was 27 years old and the mechanical shark, three of them, all nicknamed 'Bruce' after his lawyer, kept breaking down in the saltwater. The young director was forced to rewrite scenes to keep the shark off screen for most of the movie, which turned out to be its genius. What you don't see scares you more. The shoot ran 100 days over schedule and millions of dollars over budget, and Spielberg was certain his career was finished. Then it opened in June 1975 and invented the summer blockbuster. People lined up around the block.