Chiesa di Santa Maria degli Angeli

Lonely Planet review

Facing onto Piazza della Repubblica, this hulking basilica occupies what was once the central hall of Diocletian's enormous baths complex. It was originally designed by Michelangelo in 1593 but only the great vaulted ceiling remains from his innovative plans.

Today the chief attraction is the double meridian in the transept, one tracing the polar star and the other telling the precise time of the sun's zenith (sunlight enters through a hole to the right of the window above the entrance to the church's right wing). Inaugurated by Pope Clement XI in 1702, the sun dial was used to regulate Rome's clocks until 1846. Through the sacristy is a plaque dedicated to the thousands of Christian slaves who died while building Diocletian's baths.