The biggest and tallest clock tower in the world is the Makkah Royal Clock Tower, located in Mecca, Saudi Arabia. It is part of the Abraj Al-Bait complex, which stands just steps away from the Grand Mosque. The clock faces themselves are staggering in scale; each of the four faces is 43 meters (141 feet) in diameter, making them more than five times larger than the faces of London's Big Ben. The tower itself reaches a height of 601 meters (1,972 feet), making it one of the tallest buildings in the world. The clock faces are illuminated by two million LED lights, ensuring they are visible from up to 25 kilometers away. At the top of the tower sits an enormous crescent moon, and the entire structure serves as a hotel and shopping mall for the millions of pilgrims visiting the holy city. It is a masterpiece of modern engineering that blends traditional Islamic architecture with record-breaking scale and utility for the 21st century.