Catacomb of Priscilla in Rome

You're standing on the Via Salaria, northeast of ancient Rome, right across from the greenery of Villa Ada. It all looks fairly ordinary up here, but beneath your feet lies one of the city's largest underground cemeteries: the Catacomb of Priscilla. The entrance is in the Casa delle Catacombe, a house from 1929. It's home to the Benedictine Sisters of Priscilla, who look after the site.