Statue of Marcus Aurelius
At the center of the piazza, Michelangelo built the base for a precious work of art from the Roman era: an equestrian statue of Marcus Aurelius. That which you see in the piazza today is a copy, the original is safely tucked away inside the Capitoline Musems.
The statue was the cause of two famous misunderstandings: it’s one of the very few works in bronze that survived the Middle Ages, an era when ancient statues were melted down and their metal reused; this was because the popes, owners of the statue up to the 15th century, thought that it was of Constantine, the first Christian emperor, and thus spared it.
The second misunderstanding is tied to a legend according to which the cry of the small owl sitting between the ears of the horse is supposed to announce the end of the world. Fortunately, the event seems rather improbable since the supposed owl is actually only a tuft of hair in the horses mane!