The Pantheon was first built in the I century B.C. by Agrippa, (as it is written on the facade) son in law of Augustus. After two fires it was rebuilt by Hadrian in the II century A.D. The Pantheon, a temple dedicated to all the roman gods (Pan = all; Theon = gods) is the best preserved roman monument and this is because it became a church in VII century. Being a church the popes couldn't steal any marble or stone, differently from what happened to the Colosseum or to the Forums. The Pantheon is a sphere inserted inside a cylinder: in fact the height of the monument (from the pavement till the top of the dome) is 43.3 meters as well as the diameter of the base of the dome. Another curiosity: the dome of St.Peter is the biggest one in Rome (and in Italy) and it was designed by Michelangelo. But Michelangelo loved and admired the Pantheon so much that, when he realised the dome of St. Peter he wanted to make the diameter of the base few centimeters smaller than the one in the Pantheon: this was his personal tribute to the greatness of the latter. So, dimension wise, St. Peter has the biggest dome of Rome but the one with the largest diameter at the base is the Pantheon's one.
