The Birds

Hitchcock refuses to explain a thing, and nobody since has had the nerve to copy that. The birds of a California coastal town begin attacking without cause, escalation without motive, and the film ends without resolution or even a musical score, just the sound of wings.

The set pieces, the schoolyard, the gas station, the final walk to the car, are masterpieces of mounting dread, and the refusal to supply a reason is what makes it linger. Later natural-horror films always explain themselves; this one knows better.

The template for the whole genre, and still the one with the most nerve.