The Basilica di San Marco a Venezia (Saint Mark's Basilica ) is the most famous of Venezia's churches and one of the best known examples of Byzantine architecture. It lies on Piazza San Marco (in the San Marco sestiere or district) adjacent and connected to the Doge's Palace. Originally it was the "chapel" of the Venetian rulers, and not the city's cathedral. For its opulent design, gilded Byzantine mosaics, and its status as a symbol of Venetian wealth and power, from the 11th century on the building was known by the nickname Chiesa d'Oro (Church of gold). The upper order of the interior is completely covered with bright mosaics containing gold, bronze, and the greatest variety of stones. The decorated surface is about 8000m².