The Cupola, Florence Filippo Brunelleschi started in 1420 with the construction of the CUPOLA. The diameter of the inner span (m. 41.50) is close to the maximum limit for any kind of masonry dome. Instead of recuperating precedent techniques, Brunelleschi invented a technique based on his knowledge of the "way of building" of the Romans which he put at the service of a new concept and new kinds of technical, cultural, aesthetic problems, involved in the realization of the cupola. Basically the construction of the dome depended on the use of a building technique capable of avoiding any dangerous discontinuity in the masonry (27,000 tons). The cupola was thus built as a self supporting growing form. The dome is surprisingly modern: in this double shell, the lighter exterior cupola protects the inner cupola from the elements, while the two work together thanks to the powerful connecting ribs. Completed in 1436, the Cupola is the most characteristic feature of the Florentine skyline, symbolising a great cultural tradition and the city's civic awareness. The Cupola's interior has been decorated by Giorgio Vasari (1511-1574) and Federico Zuccari (c. 1540-1609) with a huge fresco representing the Last Judgement.