Though the first rule of Fight Club may famously be to not talk about Fight Club, there's something Tyler Durden forgot to take into account while crafting these guidelines: He didn't say anything about sharing photos, more specifically, behind-the-scenes snaps from the iconic 1999 David Fincher flick. 

From practice brawls to Polaroid selfies, here are 18 moments from the making of Fight Club you can't help but talk about.