Big Ben is probably the world's most famous clock. That iconic silhouette is instantly recognisable and is one of the most Instagrammed landmarks on the planet. Six monarchs and 41 prime ministers have come and gone since the bells first struck their now familiar music across Westminster.

The most famous clock in the world is widely considered to be Big Ben in London, although "Big Ben" is technically the name of the Great Bell inside the structure, while the tower itself is named the Elizabeth Tower. Completed in 1859, the Great Clock of Westminster is famous for its four massive clock faces and its incredible accuracy, which is maintained by adding or removing old British pennies from the pendulum. Another major contender is the Prague Astronomical Clock (Orloj), the oldest astronomical clock still in operation, which draws massive crowds every hour to watch the "Walk of the Apostles" and its intricate medieval dials. In the United States, the clock in Grand Central Terminal is an icon of New York City, often cited for its four-faced opal dial valued at millions of dollars. However, in terms of global recognition, cultural impact, and its role as a symbol of a nation, the Great Clock at the Palace of Westminster remains the definitive answer. Its distinctive "Westminster Chimes" are recognized across the globe, and its silhouette is the primary architectural landmark associated with the city of London.