Old Saint Peter's, Rome

St Peter's Basilica in Rome is arguably the most important church in Western Christendom, and is among the most significant buildings anywhere in the world. However, the church that is visible today is a youthful upstart, only four hundred years old compared to the twelve-hundred-year-old church whose site it occupies. A very small proportion of the original is now extant, entirely covered over by the new basilica, but enough survives to make reconstruction of the first St Peter's possible ...