The vast majority of the people living in Roman cities lived in cramped apartment buildings called insulae. Insulae were generally three to five stories high and housed from 30 to 50 people. The individual apartments usually consisted of two small rooms.
The bottom floor of the insulae often housed shops and stores that opened out to the streets. The larger apartments were also near the bottom with the smallest at the top. Many insulae were not constructed very well. They could be dangerous places if they caught fire and sometimes even collapsed.