Columns in antiquity often had a symbolic connotation of ascent into or connection with the heavens; many Roman examples exist, often associated with the apotheosis/deification of an emperor. This 19th Catholic column was erected to commemoration the Immaculate Conception of Mary, and symbolizes her exaltation as the Queen of Heaven crowned with stars (Revelation 12:1–3).
(Near the Church of the Trinity of the Mountains (Trinita dei Monti) near Piazza di Spagna, Rome)