Access to the main chapel of the Basilica of San Francesco to see Piero della Francescas Legend of the True Cross, one of the supreme masterpieces of Renaissance fresco painting, is by timed ticket to protect the delicate works. Ticketed admission allows visitors to admire the luminous cycle up close and learn about its symbolism and technique. Standing before these world-famous frescoes is an unforgettable experience and the single most important cultural attraction in Arezzo.