Filippo Brunelleschi's Dome
The technology required to build Brunelleschi's dome did not exist when construction began. When asked about chances of success, he promised the first 57 feet, after which "only practical experience will teach that which is to be followed.”
More than 4 million bricks and 15 years later, the dome was complete, rising 108 feet in the air (278 in total) spanning an area 144 feet in diameter. It remains the largest masonry dome in the world.
For giving Florence the glory it had always craved, Filippo Brunelleschi was not only buried in the crypt of the Santa Maria della Fiore, he was also immortalised in marble and placed next to the dome, to gaze up at the miracle he had wrought, for all eternity.
More information: https://www.youtube.com/watch?v=kkBaxFuh40E