Insulae were ancient Roman apartment buildings that housed the urban population, particularly the lower and middle classes. Typically constructed of wood and brick, these multi-story structures could reach up to six stories high. Insulae often featured small, cramped living spaces, with amenities like running water and communal latrines shared among residents. The design of insulae reflected the growing demand for housing in bustling cities like Rome. They were often built around a central courtyard and could accommodate many families. Due to their construction materials, insulae were vulnerable to fires, which posed a significant risk to their inhabitants.