Did you know that the huge gold ball that sits on top of the Cathedral in Florence once fell off? It gathered pace as it rolled down Brunelleschi’s dome and crashed into the piazza below. Next time you are in Florence, search for the gold cross that marks the spot.

UPDATE: 28 OTTOBRE 2018
It is said that Michelangelo, before leaving for his trip to Rome, turned towards il Duomo (as it is called by the Florentines) and said the following about the dome of St. Peter’s, which he would soon begin to build: «I go in Rome to make your sister bigger but not more beautiful>>.

Florence’s Cupolone, aka il Duomo, is the largest dome ever built without the use of ribs to support the masonry. When the great work was finished, only the golden copper ball surmounted by a cross was missing. This was then made by Verrocchio, weighing 4368 pounds.  Luca Landucci, a contemporary historian relates in his “Florentine Diary: that on 27 May 1471, the golden copper ball was raised up onto the top of the lantern of the dome of Santa Maria del Fiore. And on the 30th, they put the cross in on the ball.
The contract with Verrocchio specifically provided that the ball was to be made of eight pieces. To buy the best copper, which came from Cyprus or Central Europe, the artist spent a few months in Venice, awaiting the arrival of the correct cargo. Six pieces of copper were then sent to Florence on a wagon, going through Bologna, in August of 1469. The final two pieces arrived in Florence in October.

The finished ball and cross were installed and everything went well until April 5, 1492, when a thunderbolt crashed into them and more than the third of the lantern fell to the ground.

The damages were repaired, but in 1601, on a stormy night between the 26th and 27th of January, another thunderbolt hit the golden bronze ball and its cross. All of them crashed off the top of the dome, even bringing  down pieces of marble from Manetti’s lantern. Amazingly, despite the violence and weight of the falling structures, no one was killed or even hurt. Many of the fragments ended up in the middle of via de’ Servi, and many Florentines rushed to the Piazza del Duomo, frightened by the loud noise.
Ferdinand II, Grand Duke of Florence, immediately started the reconstruction and called upon the greatest Florentine architects, as we can see from the ancient documents. The ball with the cross was restored and put back in its place in 1602 but, as reported by the documents in the Opera del Duomo, Ferdinand concluded that the best way to defend the Duomo from what were believed to be attacks by the devil (who was said to have made the lightening) was through religion, which he quickly embraced.
Thus, at the behest of the Grand Duke and the archbishop, 2 lead cases were made to go inside the new golden copper orb. Inside were some Agnus Dei – wax medallions with the image of the Lamb, blessed in the week of Easter – and relics of saints. These objects were supposed to protect the cathedral from the thunderbolts and Latin inscriptions on the cases confirmed the contents.
The ruinous fall of the orb and cross caused so much fear that the leaders of the Florentine Republic decided to install a round, white marble slab, to show the exact point where the bronze ball crashed to the ground on the pavement behind the cathedral in front in via dell’Oriuolo.
Source: Secret Florence.