Back to the Future is a 1985 science fiction adventure film directed by Robert Zemeckis, co-written by Bob Gale and produced by Steven Spielberg. The film stars Michael J. Fox as Marty McFly, as well as Christopher Lloyd, Crispin Glover, Lea Thompson and Thomas F. Wilson. Back to the Future tells the story of Marty McFly, a teenager who is accidentally sent back in time from 1985 to 1955. He meets his parents in high school, accidentally attracting his mother's romantic interest. Marty must repair the damage to history by causing his parents to fall in love, while finding a way to return to 1985.

Zemeckis and Gale wrote the script after Gale mused upon whether he would have befriended his father if they attended school together. Various film studios rejected the script until the box office success of Zemeckis' Romancing the Stone, and the project was set up at Universal Pictures with Spielberg as executive producer. Eric Stoltz was originally cast as Marty McFly when Michael J. Fox declined as he was busy filming the TV series Family Ties, but during filming Stoltz and the filmmakers decided Stoltz was miscast so they asked Fox again and he managed to work out a timetable so he gave enough time and commitment to both: the subsequent recasting meant the crew had to race through reshoots and post-production to complete the film for its July 3, 1985 release date.

When released, it became the most successful film of the year, grossing more than $380 million worldwide and receiving critical acclaim. It won the Hugo Award for Best Dramatic Presentation and the Saturn Award for Best Science Fiction Film, and also earned Academy Award, BAFTA and Golden Globe nominations. Ronald Reagan even quoted the film in the 1986 State of the Union Address, and in 2007, the Library of Congress selected it for preservation in the National Film Registry. It marked the beginning of a franchise, with Back to the Future Part II and Back to the Future Part III released back-to-back in 1989 and 1990, as well as an animated series and theme park ride.

Plot

Marty McFly is a 17-year-old living in Hill Valley, California. On the morning of Friday, October 25, 1985, his eccentric friend, scientist Dr. Emmett "Doc" Brown (Lloyd), calls him, asking to meet at 1:15am the following morning at Twin Pines Mall. Upon arriving home from school, Marty finds the family car wrecked in the driveway, ruining his plans to spend the weekend with his girlfriend Jennifer (Claudia Wells). Inside the house, he finds his weak-willed father George (Crispin Glover) being bullied by his supervisor Biff Tannen (Thomas F. Wilson), who had borrowed and wrecked the car. At dinner that night, Marty's mother Lorraine (Lea Thompson) recounts how she and George first met when her father hit George with his car as George was "bird-watching".

The McFly house

That night, Marty meets Doc as planned in the parking lot of Twin Pines Mall. Doc presents a DeLorean DMC-12 which he has modified into a time machine. As Marty videotapes, Doc explains the car travels to a programmed date and time upon reaching 88 miles per hour using plutonium in a nuclear reaction to generate the 1.21 gigawatts of power it requires. Demonstrating how to program the machine, Doc enters in November 5, 1955 as the target date, explaining that it was the day he conceived the idea of the flux capacitor; the device which "makes time travel possible." Before Doc can depart for his planned trip into the