Must-see Movies/classic films?

I recently posted a thread on movies me and my friends should watch since we enjoy watching movies together but had no idea on what to watch. My question is very straight forward and its what are some MUST-SEE movies? I'm getting very interested in film lately and since I'm applying to colleges soon and I have no idea on what I want to do this might help me. (but its more of a excuse so I can watch movies)So yeah what are some classics I should watch? Thanks. via /r/movies http://ift.tt/2tWoro7