Big Ben is the nickname for the Great Bell of the clock at the north end of the Palace of Westminster in London. It's not actually the tower or the clock itself, but that massive bell inside. People often use "Big Ben" to refer to the whole clock tower, which is officially known as the Elizabeth Tower. It's an iconic symbol of London and a must-see for tourists visiting the city. The chimes of Big Ben are famous worldwide and have been featured in countless movies and TV shows.