Raiders of the Lost Ark is one of the most quotable action/adventure movies ever made, but its most iconic line was actually ad-libbed by star Harrison Ford. The Indiana Jones franchise has been thrilling audiences since 1981 when Raiders first hit movie screens. The adventures of the daring archeologist are often accompanied by well-placed quips and humorous beats, and one of Indy's most-loved lines in the series can be heard during a key scene in the first film.

A hallmark of director Stephen Spielberg - who helmed the first four installments in the Indiana Jones saga - is the freedom he gives his actors to improvise lines during filming. Many of Spielberg's early films featured entire scenes in which his performers made up lines in the moment. Some notable examples of this include Roy Scheider's legendary "You're gonna need a bigger boat" from Jaws, and multiple lines delivered by Richard Dreyfuss in Close Encounters of the Third Kind.

Related: Raiders Of The Lost Ark: Why Indiana Jones Shoots The Swordsman

Spielberg's tradition of allowing ad-libbing on his sets continued in Raiders of the Lost Ark, and the finished film contains several instances of improvised dialogue. Many of the actors in the film have since stated how appreciative they were of this kind of on-camera freedom, and Indiana Jones himself, Ford took part in coming up with his own dialogue during different takes. Among those lines was Indy's now-immortal musing that "It's not the years, honey. It's the mileage."

indiana jones its not the years its the milage

After having survived multiple run-ins with a group of power-hungry Nazis and finally in possession of the sacred Ark of the Covenant, Indy and Marion Ravenwood board a ship and flee from Egypt. As night falls, the two begin to unwind from their adventure, and Marion removes Indy's shirt to find his body covered in scars both new and old. As an exhausted Indy attempts to lay his aching body down, Marion remarks that he's not the man she knew when they were younger. This prompts Indy to counter with his "not the years" line, which Ford ad-libbed while the scene was being shot.

Unsurprisingly, Spielberg loved the line and kept the take. In the years since, the quote has become one of the most beloved lines from the film, and even made several appearances in merchandise for 2008's Indiana Jones and the Kingdom of the Crystal Skull, albeit reversed to read "it's not the mileage, honey, it's the years" in reference to Indy's older age in the film. Regardless of what context it has been used in, the line remains a favorite Indiana Jones quip, and proof that Spielberg's trust in his actors is a smart move.

Next: Raiders Of The Lost Ark Had A Clever Star Wars Easter Egg

Key Release Dates