For anyone who is in Florence on 21 June, you have the chance to see something very special! This is from The Florentine Weekly
The Duomo’s gnomon, an astronomical instrument should capture the summer solstice on
June 21st. The first 150 people to enter Santa Maria del Fiore at 12.30pm, will witness the sun
passing over, casting a bright circle over the exact round marble spot on the floor.
June 21, Florence’s Cathedral, piazza Duomo, operaduomo.firenze.it/eventi/r/4-lo-gnomone