Basilica of Saint Mary of the Angels and Martyrs

Designed by Michelangelo (1561) inside the surviving frigidarium of the ancient Baths of Diocletian — a unique fusion of ancient Roman and Renaissance architecture, with the original brick vaults left bare and visible above. The 45-metre-long meridian line embedded in the floor by Francesco Bianchini in 1702 was used to verify the accuracy of the Gregorian calendar; a small hole in the wall projects a beam of sunlight that crosses the line at exactly noon every day, marking the date by where it falls along the brass strip. Currently the official venue for state funerals of high-ranking Italian officials.