Big Ben, which is actually the nickname for the great bell of the Elisabeth Tower at the north end of the Palace of Westminster, is the most famous clock tower in the world.
At first glance, the four clock dials do not seem that big but they are. Each has a diameter of seven meters (23 ft.)! Each minute hand weighs 100 kg, while the hour dials weigh over 300! There are over 1,000 rooms in the palace, including the two houses of parliament, which are sometimes accessible to tourists.