When Father Mullooly decided to restore the church of Saint Clement in 1857 he would have never thought he would go down in history as the discover of the largest accessible underground site of the city of Rome. The triple-layered archeological site hosts nowadays the “modern” (by Rome’s standards!) 12th century church, the ancient church built in the 4th century and the Roman structures dating back to the first century A.D. The church is still home to a community of Irish Dominican friars and one of the places in Rome where you can attend Mass in English.