The school is a castle. It's bigger inside than outside. [ Severus hasn't felt homesick yet, not really; he felt a kind of exhausted despair being haunted by dreams of Albus, before going into the hallways and seeing those constructs of home. But it's not the same. His voice is muted, almost nostalgic. ] Two houses have dormitories in towers, two are underground. The Slytherin common room backs up underneath the Black Lake, and we have glass windows against the water on one side. The older girls' rooms have windows that can see the grounds, but they're pointed up, so they can see the stars at night and the edge of the forest.