Obviously the picture was a reference to doc brown discovering time travel, but the quote was a reference to... Remember, remember the Fifth of November,  The Gunpowder Treason and Plot,  I know of no reason  Why Gunpowder Treason  Should ever be forgot.  Guy Fawkes, Guy Fawkes, t'was his intent  To blow up King and Parliament.  Three-score barrels of powder below  To prove old England's overthrow;  By God's providence he was catch'd  With a dark lantern and burning match.  Holloa boys, holloa boys, let the bells ring.  Holloa boys, holloa boys, God save the King!