Hill Valley, California, is a fictional town that serves as the setting of the Back to the Future trilogy and its animated spin-off series. In the trilogy, Hill Valley is seen in four different time periods (1885, 1955, 1985 and 2015) as well as in a dystopian alternate 1985. The films contain many sight gags, verbal innuendos and detailed set design elements, from which a detailed and consistent history of the area can be derived.