Now I may have seriously altered history.

Dr. Emmett Brown (Christopher Lloyd)

3 seconds sound clip from the Back to the Future Part III movie soundboard.

You can hear this line at 00:46:34.915 in the DVD version of the movie.

Quote context

[...]

- Holy shit. Hey, Doc, Clayton Ravine was named after a teacher. They say she fell in there 100 years ago.

- 100 years ago! That's this year!

- Every kid in school knows that story, 'cause we all have teachers we'd like to see fall into the ravine.

- Great Scott! (3)

- Then she was supposed to go over in that wagon.

- Now I may have seriously altered history.

- Look, Doc, what's the worst that can happen, huh?

- So they don't name the ravine after her.

- Let's just get the DeLorean ready, and get the hell out of here.

- I wish I'd never invented that infernal time machine. It's caused nothing but disaster.

[...]