St. Peter’s, the largest church in the world, is a true marvel of art and engineering . Italy’s most renowned architects and sculptures Bramante, Michelangelo and Bernini all had a hand in the creation of this (excuse the pun) heavenly structure. Inside the art work on display leans towards mosaics and sculpture, the most celebrated being Michelangelo’s heartbreaking “Pieta”. There are also the beautiful reliefs on the imposing bronze “Holy Door”, but they are only opened for special occasions.