Giorgio Vasari died before he was able to complete the massive arched fresco The Last Judgement. Vasari died in 1574, and the massive project would take Federico Zuccaro 5 more years to complete. Designed to instill both reverance and fear among the congregation below, the cupola is depicted as a temple — where sit twenty-four elders of the Apocalypse. On the terraces below are choirs of angels, then groups of saints, then personifications of the gifts of the Holy Spirit, the virtues, and the beatitudes.
The lowest tier, and most visible to visitors to the Duomo, is a gristly vision of hell replete with tortured sinners.
Reed Enger, "The Last Judgement," in Obelisk Art History, Published February 15, 2016; last modified May 19, 2021, http://arthistoryproject.com/artists/giorgio-vasari/the-last-judgement/.