On this tour you will explore three of the most important Basilicas in the world, after St. Peter's: St. John Lateran, St.Mary Major and St. Paul Outside the Walls. Built in the 4th century by the emperor Constantine, the Basilica of St. John Lateran is the oldest church in the western world. A former seat of the papacy, and the current seat of the Archdiocese of Rome, St. John Latera is Rome's Cathedral. Its many treasures include the original doors of the Roman Curia or senate house. Nearby are the Scala Sancta ( Holy Stairs ) believed to be the very steps on which Chist stood trial before Pontius Pilate. St. Mary Major is one the oldest churches dedicated to Mary, the Mother of Jesus, and is known for its mosaics featuring scenes from the life of Mary. It also houses the relic of Christ's manger. Last but not least, the Basilica of St. Paul Outside the Walls is the second largest Basilica after St. Peter's Basilica. It was founded on the burial ground of St. Paul.