Step inside and the stripes continue, now in colored marble, primarily black and white, echoing the city's coat of arms. The facade itself, in white marble and Prato serpentine, mirrors the interior's division into three naves, with three portals leading in. Keep an eye on the marble floors beneath your feet, and look up toward the dome. The list of artists tied to the cathedral's completion and decoration is astonishing: Nicola and Giovanni Pisano, Donatello, Pinturicchio, Lorenzo Ghiberti and Bernini. Nicola Pisano's octagonal pulpit, completed in 1268, is often described as a turning point in European sculpture, the moment when Italian carving broke decisively from its Byzantine past. In the left transept, the funeral monument of Cardinal Riccardo Petroni was erected between 1317 and 1318 by the Sienese sculptor Tino di Camaino, and it is the earliest example of fourteenth-century funeral architecture. Two more treasures reward a slow look. The Piccolomini Altar carries figures by Michelangelo, among the most overlooked major works in Italian art. And the Chapel of the Madonna del Voto was designed by Gian Lorenzo Bernini in 1661, commissioned by Pope Alexander the Seventh, Fabio Chigi, of the Sienese Chigi family. It is Bernini's only major architectural contribution to Siena, a piece of Roman High Baroque set within a medieval church.