Slughorn's Staircase

Slughorn's Staircase is one of the largest staircases in Hogwarts School of Witchcraft and Wizardry. It extends from the dungeons to the seventh floor. It has other exits on the first, third, fifth, and sixth floors. The layout of the staircase is very similar to the Divination and Defence Against the Dark Arts Staircases, but the bottom (at dungeon-level) seems to have been excavated in the cliffs and, thus, the walls and the staircase itself are rough stone.