The Dark Tower is a small but high tower near the Transfiguration Courtyard at Hogwarts Castle. This tower seems to be used as a prison. It has several prison cells, with the topmost being at the roof. The cells are not, however, charmed or otherwise protected against breaking-in from the outside. It has seven floors. There are four gargoyles on the sides of the tower which direct water away from the tower when it rains.