We enter the mind of a prisoner of the Spanish Inquisition. The dank prison room is without light and he begins to feel his way around the walls. Later, as a little light enters the room, he discovers two things: a deep and dangerous pit in the centre into which he had almost fallen when he explored the cell blindly, and a scythe-like pendulum suspended from the ceiling which is slowly descending as it swings back and forth with his body as its target. You'll feel his terror.
Librarian's note: this entry is for the short story, "The Pit and the Pendulum." Collections of the author's stories, including the one in which this story is the title work, "The Pit and the Pendulum and Other Stories," can be found elsewhere in Goodreads.