It was 6am on November 4, 1966 when the Arno broke, after more than a century, its dikes, devastating Florence. Even today, some of the city’s palazzos bear marks showing just how high the water reached. It was in those days that the expression “mud angels” was born. Thousands of young people who came from all over the world to help Florentines shocked by the tragedy and scramble to recover the works of art submerged by raging waters. Among them, future US Senator Ted Kennedy, singer Joan Baez and young German politician Gerhard Schroeder. The Opificio delle Pietre Dure has, since then, worked to restore masterpieces damaged in the flood. This year, the city remembers those days through exhibitions and events.