This is something I've been wanting to make for a long time now. Back to the Future is one of my favorite films of all time. Yes, I know that a lot of people have made these already, but I wanted to make one with the different timelines and descriptions for each one plus a neat design! ;)
Doc explains in the movies that whenever a person time travels to the past and alters key-events, he deletes his timeline and a new timeline is created.
Ripple effect explanation: Whenever a person travels back in time and changes things in the past, things and people in the future may change. Because of this, the people in the future are sent to the new timeline that the person travelling back in time created.
If you're interested, this is available as a Print. :)
If I've made any spelling and/or grammatical errors, please tell me!