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. It is still described by its operators as "the world's tallest cantilevered observation wheel" (as the wheel is supported by an A-frame on one side only, unlike the Nanchang and Singapore wheels).

The London Eye, or Millennium Wheel, was officially called the British Airways London Eye and then the Merlin Entertainments London Eye. Since 20 January 2011, its official name is the EDF Energy London Eye following a three-year sponsorship deal.

The London Eye is located in the London Borough of Lambeth at the western end of Jubilee Gardens, on the South Bank of the River Thames between Westminster Bridge and Hungerford Bridge. The site is adjacent to that of the former Dome of Discovery, which was built for the Festival of Britain in 1951.

London ⁱ/ˈlʌndən/ is the capital city of England and the United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its founding by the Romans, who named it Londinium. London's ancient core, the City of London, largely retains its square-mile mediaeval boundaries. Since at least the 19th century, the name London has also referred to the metropolis developed around this core. The bulk of this conurbation forms the London region and the Greater London administrative area, governed by the elected Mayor of London and the London Assembly.

London is a leading global city, with strengths in the arts, commerce, education, entertainment, fashion, finance, healthcare, media, professional services, research and development, tourism and transport all contributing to its prominence. It is the world's leading financial centre alongside New York City and has the fifth-largest city GDP in the world (and the largest in Europe). London has been described as a world cultural capital. It was the world's most visited city during 2011 and London Heathrow is the world's busiest airport by number of international passengers. London's 43 universities form the largest concentration of higher education in Europe. In 2012 London will become the first city to host the modern Summer Olympic Games three times.