The Clock Tower on the north side of the Piazza San Marco. The tower and clock date from the last decade of the 15th century. At the top of the tower are two bronze figures which strike the hours on a bell. One is old and the other young, to show the passing of time. Below is the winged lion of Venice with the open book, before a blue background with gold stars. Below again, are statues of the Virgin and Child with two large blue panels showing the time: the hour on the left and the minutes on the right. Below this is the clock face in blue and gold engraved with the 24 hours of the day in Roman numerals. A golden pointer with an image of the sun moves round this circle and indicates the hour of the day. Within the marble circle beneath the sun pointer are the signs of the zodiac in gold which revolve slightly more slowly than the pointer to show the position of the sun in the zodiac. In the middle of the clockface is the earth and the moon, which revolves to show its phases, surrounded by stars which are fixed in position.