The British Parliament's Big Ben bell is due to sound the hour for the last time before it is silenced for repair work scheduled to last until 2021.
After 12 deep bongs at noon Monday, the bell will begin its longest period of silence since it first sounded in 1859.
The break will allow workers to carry out much-needed maintenance to the Victorian clock and clock tower, but will deprive Londoners and tourists of one of the city's iconic sounds.
Some lawmakers have criticised the lengthy silence, calling Big Ben an important symbol of British democracy. They want the time scale for repairs tightened.
Big Ben is not due to resume regular timekeeping until 2021, though it will be heard on special occasions such as New Year's Eve.