The Joseph Chamberlain Memorial Clock Tower is the tallest freestanding clock tower on Earth, even topping out the Elizabeth Tower that houses Big Ben in London.

The largest and tallest free-standing clock in the world is the Makkah Royal Clock Tower in Mecca, Saudi Arabia. Standing at 1,972 feet (601 meters), it is part of the Abraj Al Bait complex. The clock itself is a marvel of engineering: it features four faces, each measuring 141 feet (43 meters) in diameter—roughly 35 times larger than the face of Big Ben. Each face is adorned with over 98 million pieces of glass mosaic and is illuminated by two million LED lights, making it visible from over 15 miles away. The "Megaclock" sits atop the world's fourth-tallest building and serves as a vital timekeeper for the millions of pilgrims visiting the Masjid al-Haram. While the Elizabeth Tower (Big Ben) is more historically famous, the Makkah Clock Tower is the undisputed heavyweight champion in terms of sheer scale, height, and modern technological integration, having been completed in 2012 as the centerpiece of a massive modernization project.