‘Are you insane? We can't make a movie like this...' 10 things you never knew about Back to the Future

Great Scott, that’s shocking!
Director Robert Zemeckis' sci-fi trilogy, which began in 1985, still remains hugely popular today, with new generations falling in love with Marty McFly and Dr. Emmett Brown and their exciting time-travelling escapades.
However, did you know that writer Bob Gale and Zemeckis got turned down by Disney and that Michael J. Fox who played Marty didn't sing 'Johnny B. Goode' at the school dance?
Here are 10 facts about 'Back to the Future' that will surprise you...