One of the many treasures in Rome, this tiny building by Bramante is a classic example of Renaissance architecture, a history of architecture lesson in one. It is within a cloister of the church of S. Pietro in Montorio and is thought to be the site of the inverted crucifixion of S Peter, hence its classification as a martyrium. It seats 10.
Bramante's rather larger dome of St Peter's can be seen from here.
Where S Peter was crucified in centre of Tempietto floor