On Thursday we took a tour of the excavations under St. Peters Basilica, which you have to get tickets for way in advance.  The project ran from the late 1930s to the 1950s.  They uncovered a pre-christian necropolis - which is a town of the dead.  The necropolis was later put to use by early Christians, and St. Peter was said to be buried somewhere down there.  The original St. Peters Basilica was said to have been built over/around what was thought to be the original marker of St. Peter's grave, but until the excavation project no one was sure whether this was true.  The project found bones of a man who would have been the right age, in a grave with Christian markings.  

After the tour, and a quick visit to the Basilica, we had lunch and then went through Castel St. Angelo. This was originally built as a mausoleum for Hadrian and his family but was later repurposed as a home and fortress for the Pope.  

View from Castel St. Angelo

View of Castel St. Angelo, and a random car