In 1955, Doctor Emmet Lathrop Brown was standing on a toilet hanging a wall clock when he slipped and beat his head on the bathroom sink. Unconscious, Doc had a vision. And that vision was that of a flux capacitor -- the device that makes time travel possible. The rest, my friends, is history. Or should I say, future? Time travel joke!
Thanks to Zach, who doesn't need roads where he's going.