Basilica of St. Mary of the Angels and the Martyrs

Standing before us today was once the vast antechamber and the Tepidarium (the warm bathroom) of the Baths of Diocletian, which is quite evident from the eight huge granite columns, each measuring 14 metres in height and 1 ½  metres in diameter.

On entering our attention is immediately caught by the double meridian on the floor of the transept: the sun, filtering from a hole placed to the right of the window above the right nave’s entrance, indicates the position of the Polaris or North Star and the precise time it reaches its zenith (midday). Unveiled by Pope Clement XI in 1702, it was used to check the accuracy of the calendar right up until 1846