I Quattro Canti -- the four corners at the center of the old city.
At the intersection of Corso Vittorio Emanuele and Via Maqueda in the heart of the old town, the Quattro Canti is also known as the theater of the sun. I do not know who took this fine picture, but whoever it was lay down in the center of a busy intersection on a cloudless day and shot upward toward the cerulean blue sky.