Dome of Santa Mario del Fiore
The dome of Santa Maria del Fiore wasn't even started until at least 100 years after construction of the church began. And it had to be bigger and better than any other dome ever built. Neri di Fioravante designed the dome but Brunelleschi was assigned to actually execute the construction. He decided that, because of the sheer size of the dome, he shouldn't use stone. He should use bricks since they are lighter and easier to make. Even though bricks are lighter than stone, they are still very heavy when you have 4 million of them. So, Brunelleschi designed and built some machines to lift the bricks to the workers who were 52 feet off the ground. The dome was eventually finished in 1469; 173 years after it was started.