The Elizabeth Tower is the clock tower of the Palace of Westminster in London, England.[1] It contains the Great Clock, a striking clock with five bells.[2] The tower is nicknamed "Big Ben", which was originally a nickname for the largest bell (named the Great Bell).[3] The tower was officially called the Clock Tower until 2012, when it was renamed to mark the Diamond Jubilee of Elizabeth II.

The tower was designed by Augustus Pugin in a Perpendicular Gothic Revival style and was completed in 1859. It is elaborately decorated and includes symbols related to the four nations of the United Kingdom, the Tudor dynasty, and a Latin inscription to Queen Victoria.[4] The tower stands 316 feet (96 m) tall, and the climb from ground level to the belfry is 334 steps. Its base is square, measuring 40 feet (12 m) on each side. The dials of the clock are 22.5 feet (6.9 m) in diameter.

The clock uses its original mechanism and was the largest and most accurate four-faced striking and chiming clock in the world upon its completion.[5] It was designed by Edmund Beckett Denison and George Airy, the Astronomer Royal, and constructed by Edward John Dent and Frederick Dent. It is known for its reliability, and can be adjusted by adding or removing pre-decimal pennies from the pendulum. The Great Bell was cast by the Whitechapel Bell Foundry and weighs 13.5 long tons (13.7 tonnes; 15.1 short tons).[1] Its nickname may be derived from Sir Benjamin Hall, who oversaw its installation, or heavyweight boxing champion Benjamin Caunt. There are four quarter bells, which chime on the quarter hours.

The Elizabeth Tower is a British cultural icon. It is one of the most prominent symbols of the United Kingdom and parliamentary democracy,[6] and it is often used in the establishing shot of films set in London.[7] The clock tower has been part of a Grade I listed building since 1970 and a UNESCO World Heritage Site since 1987.[8] The fabric was repaired and renovated between 2017 and 2021, during which the bells remained silent with few exceptions.[9]