Basilica of St. John Lateran

We stopped here as it was adjacent to Scala Sancta. We didn't realize this was the top Papal Basilica in the world and is the oldest christian church in the west.

I'll let wikipedia explain it: "The Papal Archbasilica of St. John in the Lateran (Italian: Arcibasilica Papale di San Giovanni in Laterano), commonly known as St. John Lateran's Archbasilica, St. John Lateran's Basilica, St. John Lateran, or just The Lateran Basilica, is the cathedral church of the Diocese of Rome and the official ecclesiastical seat of the Bishop of Rome, who is the Pope.

It is the oldest and ranks first among the five Papal Basilicas of the world and the four Major Basilicas of Rome (all of which are also Papal basilicas), being the oldest church in the West and having the Cathedra of the Bishop of Rome."Read more