1.21 Gigawatts! Run for it, Marty! It's one of the most quotable movies from the 1980s, filled with comedy, action, history, rock n' roll, and science. He's trapped in 1955 and he needs to get back to 1985, the year of Huey Lewis and the News and Pepsi Free. And only Doctor Emmett Brown can help him get Back... to the Future! Here we look at 10 things you never knew about Back to The Future.

The Original Marty McFly.

Related: DeLorean Estate Sues Over Missing Back to the Future Payments

Eric Stoltz Back to the Future

It's arguably the best-known part of the Back to the Future lore. Director Robert Zemeckis wanted Michael J. Fox to play the lead, but the young actor was simply too tied up with the hit sitcom Family Ties. So the acclaimed star of the movie Mask, Eric Stoltz, was cast as Marty McFly instead. What's lesser known is exactly how much of the movie was shot with Stoltz, who learned to skateboard and play guitar for the part. Tom Wilson, who played bully Biff Tannen, has said Stoltz was a bit "method." Christopher Lloyd was apparently so used to calling him "Marty" that he didn't realize Eric was his actual first name till after the part was recast. All of his scenes were eventually reshot with Michael J. Fox, of course, but Stoltz was able to reunite with his pal Lea Thompson. The two costarred in 1987's Some Kind of Wonderful.

The Potential Marty McFlys.

Marty McFly

Before Stoltz was hired and fired and Fox finally agreed to make it work with his already exhausting television shooting schedule, a number of other actors were considered for the role of Marty McFly. Those names include Johnny Depp, John Cusack, Ralph Macchio, and C. Thomas Howell, who was said to be in close contention with Stoltz.

The potential Doc Browns.

Doc Brown

Christopher Lloyd, part of the ensemble of the TV series Taxi which ran from 1978 till 1983, seems irreplaceable as Doctor Emmett Brown in the minds and hearts of fans around the world. But before he landed the role, some other big names were considered for the part, including John Lithgow, Dudley Moore, and Jeff Goldblum. Imagine those memes!

The original Biff.

Biff Back to the Future

Tim Robbins was one of the actors considered for the role of Biff before it was ultimately given to Tom Wilson. But the original Biff, at least in name, is a real person. Biff Tannen's name was a bit of an inside joke between Zemeckis and Gale, who'd had an unpleasant experience with a Universal Pictures executive during a script meeting about another movie. The name of that executive? Ned Tanen. Heh.

A Tale of Two Presidents.

Ronald Reagan

Whittier High School stands in for the fictitious Hill Valley High School in Back to the Future. It's the school attended by future President Richard Nixon, as a teenager. There's of course a great joke about Ronald Reagan, a two-term President in the '80s, in Back to the Future. Reagan reportedly enjoyed the joke so much that he asked his White House projectionist to rewind it. He even quoted Back to the Future in his 1986 State of the Union address and was said to have been offered a small role in Back to the Future III. He would have been the mayor of the Old West Hill Valley.