<Tr> <Th> Architect </Th> <Td> Augustus Pugin </Td> </Tr> <P> Big Ben is the nickname for the Great Bell of the clock at the north end of the Palace of Westminster in London and is usually extended to refer to both the clock and the clock tower . The tower is officially Elizabeth Tower, renamed to celebrate the Diamond Jubilee of Elizabeth II in 2012; before that, it was known simply as the Clock Tower . </P> <P> The tower was designed by Augustus Pugin in a neo-gothic style . When completed in 1859, it was, says horologist Ian Westworth, "the prince of timekeepers: the biggest, most accurate four - faced striking and chiming clock in the world". It stands 315 feet (96 m) tall, and the climb from ground level to the belfry is 334 steps . Its base is square, measuring 39 feet (12 m) on each side . Dials of the clock are 23 feet (7.0 m) in diameter . On 31 May 2009, celebrations were held to mark the tower's 150th anniversary . </P> <P> Big Ben is the largest of five bells and weighs 13 ⁄ long tons (13.7 tonnes; 15.1 short tons). It was the largest bell in the United Kingdom for 23 years . The origin of the bell's nickname is open to question; it may be named after Sir Benjamin Hall, who oversaw its installation, or after boxing heavyweight champion Benjamin Caunt . Four quarter bells chime at 15, 30 and 45 minutes past the hour, and also just before Big Ben tolls on the hour . The clock uses its original Victorian mechanism, but an electric motor can be used as a backup . </P>

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