Catacomb of Saints Gordian and Epimachus
Rome, Italy
The Catacomb of Santi Gordiano e Epimaco is a catacomb on the ancient via Latina in Rome, near the Aurelian Wall and piazza Galeria in the Appio-Latino quarter. Only some of its galleries have been found and excavated - archaeologists believe it to be a much larger necropolis on several levels, with inscriptions from Julian's reign showing it to have still been in use at that date.
Archaeological site data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).