Time briefly stood still as the clock's hands were frozen shortly after 8 a.m. They then were wound to 12 o'clock as a team of specialist "industrial rope-access technicians" descended to clean the clock's four latticework faces, part of maintenance ahead of its 150th anniversary in 2009.

Although the clock soon will be ticking again, the famed bell that sounds the hour at Britain's Houses of Parliament will be silent for four to six weeks as engineers replace bearings in the clock mechanism.

This is the first time since 1956 that both Big Ben's sonorous hourly bongs and the chimes that mark each quarter-hour will be silent, robbing London of one of its most distinctive sounds.

Parliament's neo-Gothic clock tower, designed by Charles Barry, is popularly known as Big Ben, although the name refers only to the 13.5 ton Great Bell inside.

Cast at the Whitechapel Foundry in east London, Big Ben first rang out in July 1859. Soon after, it cracked - as an earlier version had during testing. Officials simply turned the bell so the hammer wouldn't strike the crack. That same bell, crack and all, remains in use.

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On the Net:

Big Ben and the clock: http://www.parliament.uk/about/history/big-ben.cfm