Catacombs run under much of Rabat. Up Triq Santa Agatha from Parish Square, the Catacombs of St. Paul are clean of bones but full of carved-out burial troughs. Don't forget the way out when you set off to explore. St. Agatha's Crypt and Catacombs, farther up the street, were beautifully frescoed between 1200 and 1480, then defaced by Turks in 1551.
St. Agatha St., Rabat, RBT 2013, Malta