Filippo Brunelleschi, a goldsmith, engineer, and relatively inexperienced architect, completed the largest masonry dome in the world in 1436—a record that has never been broken. The world now knows it as Brunelleschi’s Dome, which sits atop the Cathedral of Saint Mary of the Flower in Florence, Italy.

When completed, the dome was 52 meters (171 feet) high, with an exterior diameter of 45.5 meters (149 feet) and an interior diameter at its base of 41 meters (135 feet). The base of the dome sat above the crossing of the Cathedral, which was 55 meters (180 feet) above the ground. Atop the dome was a lantern measuring 21 meters (69 feet) in height, bringing the entire Cathedral structure to a remarkable 128 meters (420 feet). While it was not the tallest structure in the world at the time—Lincoln Cathedral in England, at 160 meters (525 feet), held that distinction—it was certainly an impressive architectural feat.

Trivia: Brunelleschi developed an ingenious mechanical lift to raise materials up to the dome. The modern world knows what that device looked like and how it worked because a young Leonardo da Vinci sketched the hoist when he was apprenticed to the Florentine painter Verrocchio beginning in 1466. Due to that sketch, Leonardo was sometimes mistakenly given credit for inventing the hoist.

Source: Brunelleschi’s Dome by Ross King, 2000. Graphic: Brunelleschi’s Dome by National Geographic, 2013-2019.