The movie is set at three different times;
- the early 1920s; the characters as children,
- the early 1930s; the characters as adults,
- 1968; the few still living characters in their old age.
When Leone finished making the movie it was 229 minutes (3 hours and 49 minutes) and started with an old character (Robert De Niro) remembering his past; it then showed him as a child and as a young adult. We call this flashbacks; it can happen in movie but certainly not in real life. But when it was first shown to American audiences it was made much shorter and set in chronological order; meaning the movie first showed the characters as children, then as young adults and then as older adults; or 'from start to finish'. We call this chronological; this is what would happen in real life. Many people agree that the longer version is much better than the shortened chronological version.