The central hotel tower, which is the Makkah Clock Royal Tower, is the fourth-tallest building and sixth-tallest freestanding structure in the world. The Makkah Royal Clock Tower is a triumph of engineering.At 35 times the size of Big Ben it has the world's largest clock. At 1,046 ft (319 m), it is the tallest brick building in the world with a steel framework. Clock moves with wind up motor. Fiddly gears but take time and it works reasonably well. Discover the history and significance of Big Ben, the iconic clock tower that stands tall over the city of London.