Sant' Agnese fuori le Mura is a 7th-century church built over catacombs on the Via Nomentana. Its unusual layout reflects the site: the nave sits down at catacomb level, while the street entrance reaches the upper gallery.
The church stands beside the mausoleum of Santa Costanza and is closely tied to the cult of Saint Agnes, whose body lies in a silver sarcophagus. It is a good stop for visitors interested in early Christian Rome away from the busiest central churches.