Big Ben is the nickname for the great bell of the clock at the north-eastern end of the Palace of Westminster in London, and is often extended to refer to the clock or the clock tower as well.

Big Ben is the largest four-faced chiming clock and the third-tallest free-standing clock tower in the world. It celebrated its 150th anniversary in May 2009 (the clock itself first ticking on 31 May).

it is the most famous icon of London.