Yes, it's the one with the famous quote.
"Forget it, Jake, it's Chinatown."
Jake Gittes gets so much more than he bargained for over the course of Chinatown's two hours. Every move he makes turns out to be the wrong one, every clever deduction is too little and far, far too late. Every conversation he has rings home the single overarching point: you think you've got it figured out, but you have no idea.
It all culminates with Jake attempting to get Evelyn and her sister/daughter (another great scene that just barely missed the list) into Mexico and away from the intensely evil (and incredibly transfixing) Noah Cross. Unfortunately, Cross has the police in his back pocket. Evelyn refuses to let him have her daughter, Cross refuses to let her go.
Judging by the noir-ish atmosphere, you can just about guess how this ends...
The most gut kicking part? Jake's muted "as little as possible" remark.
Annoyingly broken up into two sections on YouTube. Here are both of them.