Outside, stands out the so-called Porta della Mandorla, which earns its name from the aureola encircling the figure of the Madonna in Nanni di Banco’s Assumption relief.
Inside, the church is shaped into three naves, divided by large pillars. At the base of the pillars the architectural elements begin, which culminate in the ogival vaults. The dimensions are enormous: 153 metres long and 38 metres wide. The simple and austere interior gives a distinct feeling of emptiness. The Cathedral of Florence is the first of its kind in terms of dimension and structure.
The floor in multi-coloured marble was designed by Baccio d'Agnolo and continued, from 1526 to 1560, by his son Giuliano, Francesco da Sangallo and other masters (1520-26). During the restoration work, following the 1966 flood, the discovery was made that some marbles taken from the unfinished façade, demolished at that time, had been used, upside down, in the floor.