The London Eye is a giant Ferris wheel situated on the banks of the River Thames in London, England. The entire structure is 135 metres (443 ft) tall and the wheel has a diameter of 120 metres (394 ft).
It is the tallest Ferris wheel in Europe, and the most popular paid tourist attraction in the United Kingdom, visited by over 3.5 million people annually. When erected in 1999 it was the tallest Ferris wheel in the world, until surpassed first by the 160 m (520 ft) Star of Nanchang in 2006 and then the 165 m (541 ft) Singapore Flyer in 2008. Supported by an A-frame on one side only, unlike the taller Nanchang and Singapore wheels, the Eye is described by its operators as "the world's tallest cantilevered observation wheel". It is the 20th tallest structure in London and offers the highest public viewing point in the city, although this will be superseded by The Shard skyscraper viewing deck when it opens to the public in February 2013.