Discovery Channel is rolling out its annual Shark Week starting this Sunday, and it was only last week that Syfy presented Sharknado 2: The Second One. Neither of those bizarre TV phenomena would exist if not for this 1975 Steven Spielberg film, which spawned not only a feeding frenzy of shark TV, but the entire concept of the modern movie blockbuster. But really – who needs a week of shark documentaries, or a goofy Syfy telemovie, when you can watch Robert Shaw, Richard Dreyfuss and Roy Scheider clash on the high seas, in pursuit of, and being pursued by, the greatest Great White Shark in cinema history?