Richard Donner began shooting his vision of Superman II while concurrently filming Superman The Movie - his never-before-seen vision has a totally different beginning and resolution.
Inception
Gladiator
The Empire Strikes Back
Star Wars
Avengers: Endgame
Terminator 2: Judgment Day
Avengers: Infinity War
Avatar
Return of the Jedi
Pirates of the Caribbean: The Curse of the Black Pearl