The Pantheon is the best preserved Classical building anywhere; a pagan temple, it was converted into a church in the 7C. It is entered through a portico supported by sixteen monolithic granite columns, all original save the three at the left-hand end. The interior is a masterpiece of harmony and grandeur, dominated by its original dome (as wide as the building is tall). Embellished by alternating rounded and triangular pediments, the side chapels house the tombs of Raphael and kings of Italy.