The dogma of the Immaculate Conception of the Virgin Mary was proclaimed by Pope Pius IX on 18 December 1854. Three years later, the Pope inaugurated the monument of the Immaculate Conception in Piazza di Spagna.

The Feast of the Immaculate Conception is celebrated with veneration of the Immaculate Conception monument in Piazza di Spagna, Rome. The ceremony draws in thousands of tourists, pilgrims and sightseers every year.