30 Things You Didn't Know About Tim Burton's Batman

12. "I'm Batman" Was Improvised By Michael Keaton

Mere minutes into the movie, Batman utters one of the most iconic lines in the history of superhero cinema as he dangles a criminal off a roof - "I'm Batman."

It's a simple but brilliantly effective one-liner that's endured in pop-culture for all of its 30 years, but the best thing of all? It wasn't even in the script, and Keaton himself came up with it on the spot.

The script originally called for Batman to quip, "I am the night" - referring to both the literal cover of night and The Dark Knight - but Keaton opted to change it, presumably for the sake of efficiency and simplicity.

They're both badass lines, but Keaton clearly made the right call here.