From 4 hours,2 minutes to 5 hours 25
These films are the longest complete singular films I’ve seen in one sitting

• - Zack Snyders Justice League (2021) - 4 Hours, 2 minutes

• - Cleopatra (1963) - 4 hours, 3 minutes

• - The Lord of the Rings: The Return of the King: Extended Edition (2003) - 4 Hours, 12 Minutes

• - Nymophomaniac: Directors Cut (2014) - 5 Hours, 25 Minutes

Yet to watch
• Gettysberg - Directors cut (1994) - 4 Hours, 31 Minutes• Das Boot - The Original Uncut Version (1981) - 4 hours, 53 Minutes, living in a material world (2011) - 3 Hours 47 minutes (Documentary)