A large marble circle on the square behind the Duomo marks the spot of a curious event that occurred more than 400 years ago. Most people, tourists and Florentines alike pass the marker without so much as noticing it or wondering what it means.

The story behind the marker takes us back to the night of January 27, 1601, when a terrible thunderstorm raged over Florence. Lighting struck the highest point of the Duomo: the large gilded ball with a cross on top that had been the shining symbol of the cathedral since 1472. The impact was so powerful that the ball got detached, rolled down the cupola and hit the square below with an enormous blow. On that exact spot, a circular marker was placed to remember the event of that fateful night.

The ball, designed and created by Andrea del Verrocchio, is made of gilded bronze and has a diameter of 2 meters and 30 centimeters and weights almost 2000 kilo. During the period when the ball was manufactured, a young man named Leonardo da Vinci was an apprentice in the workshop of Verrocchio, and it is more than likely that he worked on this project.

The restoration carried out by the architect Bernardo Buontalenti, took over a year and in the summer of 1602 the ball with its cross was placed on top of the cupola again.