Final answer:
Marty McFly travels back to the year 1955 in the film 'Back to the Future'. This trip is central to the plot as Marty must navigate the past while preserving his future.
Step-by-step explanation:
In the popular 1985 sci-fi film Back to the Future, the protagonist Marty McFly, played by Michael J. Fox, travels back in time to the year 1955. This event kicks off a series of adventures as Marty interacts with his younger parents and must ensure his own future existence. The journey back in time is facilitated by a DeLorean car turned time machine, invented by the eccentric Doc Brown.
The year 1955 holds significant importance in the plot, as it allows Marty to interact with his parents and impact their future relationship.