http://www.romanlife-romeitaly.com
St Peters Basilica is often referred to as a cathedral, however it is not the seat of a bishop, so it is referred to as a Basilica.
Rome's cathedral is actually San Giovanni in Laterano seat of Rome's bishop.
St Peters was the biggest church in the world, it's now 2nd biggest after
the Basilica of our lady of peace in Yamoussoukro, Ivory Coast, West Africa.
To the right off the entrance lies "La Pieta" by Michelangelo. http://www.romanlife-romeitaly.com