One of the world's most famous landmarks - Big Ben at the Houses of Parliament in London - is 150 years old.
Technically, the name refers to the clock's biggest bell. But the BBC reports it has become synonymous with the clock tower itself, which was built after fire destroyed much of the old Houses of Parliament in 1834.
The bell, cast in Whitechapel on 10 April 1858, was first rung in the Great Westminster Clock on 31 May 1859.
Clock keeper Mike McCann says it's easy to maintain, with the main work being winding it up three times a week.
Last year, Big Ben was named Britain's favourite attraction in a poll of more than 2000 adults.