The Romans truly left their mark where ever they went and Rabat on the outskirts of Mdina is no exception. The Catacombs are the earliest and largest archaeological evidence of Christianity in Malta. Explore this ancient site that consists of two large areas called St. Paul’s and St. Agatha that are comprised of a complex system of interconnected passages and tombs. The Catacombs of St. Paul are Malta's biggest catacombs and they originally date back to the 4. and 5. century. It used to be about 14.000 tombs, today there are still about 900 left. You can mainly find the Loculi-graves, in which the ordinary people were buried. The elaborate graves (canopy graves) were withhold for the aristocratic inhabitants of Malta.
http://fullofcharacter.com/index.php/en/st-paul-s-catacombs#sigProId4bb90f4176
Opening hours are daily from 9am till 5pm, for an entrance fee of 5 Euro.