Rear Window (1954)

Hitchcock made a film about a man watching his neighbors and turned the audience into accomplices. Stewart sits in a wheelchair with a broken leg and a telephoto lens and does what we'd all do: spy. Grace Kelly is absurdly beautiful and also the only person willing to actually do anything dangerous. The camera never leaves the apartment — every piece of evidence is filtered through what Stewart can see, which means you're solving the murder and questioning your own voyeurism at the same time. Elegant, slow, and earns its tension without a single chase scene.