The Basilica San Petronio in Bologna, Italy, gets a special mention as it helped Italian astronomer Giovanni Cassini, who set out to figure out the exact date of the equinox, make the first reasonably accurate prediction of the distance between the sun and the Earth, thanks to a pinhole camera mounted in the Basilica ceiling.
In 1651, Cassini tracked the light that shone through a small hole in the ceiling of the left of the basilica onto the floor, every day at midday.
His purpose was to assess whether easter, which should line up with the spring equinox, was falling on the right date in the newly-introduced Gregorian calendar.
By observing that the projected sunlight grew and shrunk throughout the year, Cassini was able to determine when the Earth was closest and farthest from the sun, proving that the Earth's orbit around the sun was not circular, but elliptical.
Tourists still visit the basilica to see the sunlight hit the floor where Cassini would have seen it.