La Jetée plot
"A man’s obsession with an image of his past."
Paris, sometime after World War III. After a nuclear battle, humanity lives underground, sheltering from the deadly radiation on the Earth's surface. Scientists are conducting experiments with time travel, hoping that the future or the past can save the desperate present. Prisoners are their guinea pigs. Most succumb to the shock of the jump in time, but one of them proves particularly successful. This is due to his strong attachment to a memory from his early childhood: at an airport he noticed a beautiful girl, and then saw a man die.