In order to save the world from a nuclear holocaust in 2045, Doc Brown must push the technological age back at least 50 years preventing Mattel Hoverboards and Mr. Fusion from being created.
2002
1985
1989
1991
2004
1955
1995
2001
1968
1993
2007
1992
2022
2024
2021
1961
1987
2008