IT The Terror From Beyond Space (1958)

Besides having the best title of any movie, IT! The Terror From Beyond Space appears to be the first film to introduce the idea of the very convenient air shaft. When the first manned expedition to Mars is invaded by an unknown entity, one brave member of the team volunteers to go poke around in the air shaft, or ventilation shaft, or ventilation duct, or whatever you want to call it.

The film treats the shaft with appropriate reverence, recognizing how unnerving it would be to go crawling around in one of those things.