Proclaimed “World Heritage Site” by UNESCO in 2015, the Cathedral of Monreale is known for its extraordinary 6400 square metres of Byzantine mosaics which decorate the interior. The Cathedral, which stands on the steep sides of Mount Caputo, was built at the behest of William II, called “The Good”: legend has it that in 1174 the Virgin Mary appeared to the sleeping king, revealing to him the place where his father, William I called “il Malo”, had hidden a treasure which, once discovered, was to be used to build a church in his honour. In addition to the many legends about the construction of this church, the Cathedral is an extraordinary example of Byzantine-Norman art and architecture. The imposing façade, closed by two corner towers and with a triphoric portico, also houses a bronze door by Bonanno Pisano, dating back to 1186. The building, with its basilica and Latin cross layout, has a nave and two aisles separated by columns which support Arab arches. The floor is made of porphyry and granite. The walls of the apses are covered with magnificent gold mosaics that represent the stories of the new and old testament and an imposing Christ Pantocrator. These and other magnificent elements make the Cathedral of Monreale one of the most beautiful buildings in Sicily.