This piazza sits bordered by Palazzo Chigi to the north, Palazzo Wedekind to the west, Palazzo Ferrajoli to the south and Galleria Alberto Sordi to the east. So many palazzos in Rome!
In the center of this square are two structures:
- the column: erected by Emperor Commodus to honor his father Emperor Marcus Aurelius, modeled after the Column of Trajan*, with a carved frieze wrapping around the column celebrating military conquests. I found it interesting to learn that the column is hollow, with stairs that lead to the top. Also similar to Trajan's Column, the original statue of the emperor at the top was replaced in the 16th century by order of Pope Sixtus V with a statue of an apostle; for Trajan it was Saint Peter and for Marcus Aurelius it was Saint Paul. .
- the fountain: water from the ancient Virgo Aqueduct flows into this 16th century fountain, emitting water from a central birdbath spout, and side spouts shaped like interlocking dolphins on each side.
For more info:
https://www.turismoroma.it/en/places/piazza-colonna
*another famous triumphal column with reliefs carved around it, celebrating the victory of Emperor Trajan in Dacia, located in the Piazza Foro Traino close to the Foro Romano (the Forum next to the Colosseum). read more