References in classic literature ?
The second grotto was lower and more gloomy than the first; the air that could only enter by the newly formed opening had the mephitic smell Dantes was surprised not to find in the outer cavern.
At last my companion paused, and directed my attention to a narrow opening in the foliage.
Presently, however, he heard a light tap at his door, then the door opened slowly, and he could see the flash of Lady Arabella's white dress through the opening.
By what mad road, through what passages of mystery and darkness known to him alone had Erik dragged that pure-souled child to the awful haunt, with the Louis-Philippe room, opening out on the lake?