Saint Peter's Basilica (Piazza San Pietro in Vatican) is the sacred place of the Catholic Church and the biggest cathedral of the Christian world. Saint Peter was martyred at this very spot at an ancient hippodrome circa 64 AC. His tomb can be found here as well, below the church that the emperor Constantine erected in his honour. During those 70 years when the Popes resided in Avignon, the church became so decrepit that it was impossible to renovate or restore. At the beginning of the 16th century the architect Donato Bramante was charged with a great task of designing and building the new cathedral. It took 176 years to complete the project! The present basilica still holds the art from the previous 4th century church built by Constantine. Many Popes are buried at the grottoes where old mosaics by Giotto can still be seen. Michelangelo worked on the gigantic dome that is 136,5 meters tall and Bernini completed the splendid baldachin. Michelangelo's famous Pieta is also located here. The pulpit in the apse is decorated by four sculptures of saints holding the throne вЂ“ it is another work of Bernini. The throne is partially made of remnants of the pulpit from which Saint Peter preached his first sermon.