It holds the largest four-faced chiming clock in the world and is the third-tallest free-standing clock tower.

Technically, the structure commonly known as Big Ben—officially named the Elizabeth Tower—is a free-standing clock tower, but it is structurally integrated into the design of the Palace of Westminster. Standing at 96 meters (315 feet), it was completed in 1859 and is the third-tallest free-standing clock tower in the world. It is "free-standing" in the sense that it is a distinct vertical shaft with its own foundation, but it is physically attached to the northern end of the Houses of Parliament. In 2026, the tower remains a global icon of London, following a massive five-year restoration completed in 2022 that addressed its slight 0.23-degree lean. While it looks like a single pillar, its base is actually built into the larger legislative complex, though its weight is supported by a 15-meter square concrete raft that allows it to stand independently of the primary palace walls.