Big Ben is the name of a large bell in the center of the clock tower located north of the Palace of Westminster, London, United Kingdom. But the name is often used to refer to the clock tower as a whole. The tower is officially named Elizabeth Tower, to coincide with the 60th anniversary of Queen Elizabeth II ruling the United Kingdom and the Commonwealth of Territories. Big Ben was completed in 1858, and as of May 31, 2009 the tower is exactly 150 years old.
Palace of Westminster and Big Ben from the northeast, from the Westminster Bridge
The tower was built as part of a plan to build a new palace by Charles Barry, after the old Palace of Westminster was destroyed by fire on the night of October 22, 1834. The tower is 96.3 meters (316 ft) high and was built in the Victorian Gothic style. The 61 meters (200 feet) below the clock are made of brick covered with stone, while the spire is supported by an iron frame made of molten iron. The tower is built on a ground measuring 15 meters by 15 meters, the foundation is made of concrete 3 meters (9 feet) thick, at a depth of 4 meters (13 feet) below the surface. All sides of the clock are 55 meters (180 feet) above the ground.
Due to changes in soil conditions since its construction, Big Ben Tower tilts slightly to the northwest by approximately 220 millimeters (8.66 inches), it tilts annually by a few millimeters to the east and west due to thermal effects.