The dome of the Florence Cathedral is perhaps the most important feat of architecture that Brunelleschi has done. In 1419, his design was chosen after the church was looking for one that would fill the hole in the roof. His design consisted of several arches designed to keep the dome standing, a practice used in Roman architecture. The dome would be completed in 1436 and was an architectural marvel, becoming the largest brick dome in the world. The success of the dome led to future construction projects incorporating the dome into their designs, which helped signal the revitalization of classical architecture that would define the Renaissance.
Source: Warren, Charles W. “Brunelleschi's Dome and Dufay's Motet.” The Musical Quarterly, vol. 59, no. 1, 1973, pp. 92–105. JSTOR, www.jstor.org/stable/741461.
Image: https://www.britannica.com/place/Cathedral-of-Santa-Maria-del-Fiore