The Third Man (1949)
One of history's films de grandeur, Carol Reed's The Third Man has got it all. It is basically a murder mystery (set in post-war black market-struck Vienna) but it works on several levels. The direction by Reed is stylishly and slickly poised. He's so confident that he can even afford to at times sacrifice suspense just to dwell on the visuals. And the photography, by Robert Crasker, is one of a kind. Some shots are classic segments of cinema in their own right - such as Orson Welles' first appearance, or the stair-crawling towards the end. The mystery is satisfyingly complex and has its fair share of surprises, but the real genius here is the diversity, intricacy and development of the characters. The performances are great too, with the devilishly charming Welles and the commanding Trevor Howard as standouts. One of the truly all-time greats.