Since it opened in 2000, the London Eye has proved to be a popular tourist attraction.
BBC News considers how it became one of the UK capital's major symbols.
The London Eye is one of the UK's most popular tourist landmarks
The London Eye is the largest, and arguably the most famous, observation wheel in the world.
At 135 metres, the Eye - which is based on the South Bank - is 30 metres higher than the wheel at Yokohama Bay in Japan, which had been the tallest.
The landmark, which can carry around 15,000 visitors a day, towers above a number of other London landmarks, such as Big Ben and St. Paul's Cathedral, and has re-shaped the UK capital's skyline.
And the wheel, which has 32 capsules each capable of carrying up to 25 people, provides visitors with views of around 25 miles from the top.
It is thought to have attracted up to 18m people and has won more than 40 awards for tourism and architecture.
In addition to the regular influx of tourists, the structure has attracted more unconventional visitors.
In August 2003 American magician David Blaine stood on top of one of the structure's pods for a complete 30-minute revolution.
And last September the Eye was forced to close after a Fathers 4 Justice campaigner scaled the wheel and spent 18 hours on top of a pod before coming down voluntarily.
The protest is just one of the problems experienced by the observation wheel since it was conceived.
It was opened behind schedule, amid fears that it would be among a number of attractions opened to commemorate the new millennium that would seem out of place after the celebrations.
Former Tory minister Lord St John of Fawsley openly criticised the wheel, which he believed would be a 'white elephant'.
He welcomed the Jubilee Line extension's award of millennium building of the year in 2000 with a barbed criticism at the expense of the Eye.
He said: "The London Transport Executive is to be congratulated on commemorating the millennium in such a brilliant and socially useful way, which will be an enduring monument to the millennium as opposed to follies like the millennium wheel, which I hope will be moved to a more suitable site at the earliest possible moment."
And last July the site was forced to close temporarily after a metal pin cover from the wheel's hub came loose and fell around 70m on to a canopy, showering people with glass.
However, nobody was injured in the incident.
But aside from these minor problems the structure, which was designed by husband-and-wife team Julia Barfield and David Marks, has enjoyed a relatively trouble-free existence.
Between 2002 and 2003, the Eye welcomed 4.1m visitors, making it London's most popular fee-paying attraction, according to figures released by Mintel last year.
Only the British Museum and Tate Modern gallery attracted more people - each of which had 4.6m visitors.
"Few people could have predicted that enormous success," said David Marks.
"It has transformed the London skyline and played an important economic role in regenerating the South Bank and in maintaining tourism for London."
The Wheel's success has helped to cement the site's image as one of London's main attractions, rather than merely being a commemorative structure to celebrate the new millennium, as it was originally conceived.
At first the Eye was only granted planning permission for five years, but in 2003 it was extended for at least 24 years.
Overall, London welcomed 11.6m overseas visitors and 16.1m UK tourists in 2002/3, making it Europe's most popular tourist destination.
The wheel has 32 observation pods providing a view of London's skyline
Paris, its nearest rival, had 9m foreign visitors.
It seems the wheel has provided a welcome boost to the English capital's tourist economy.
And the architects of London's bid for the 2012 Olympics are hoping that the site will be one of the examples of British enterprise that secures their success.
But, despite its success, the landmark's future looks uncertain.
In May 2005 the South Bank Centre (SBC), the wheel's landlords, served the owners of the structure with an eviction notice after expressing their intention to increase the rent by 1,500%.
SBC are understood to want to increase the annual rent from £65,000 a year to £1m.
If the money is not paid, the wheel could be closed down.
In an indication of the London Eye's elevated status among the UK's tourist attractions, the news prompted the Conservative party to suggest that London's Olympic bid could be damaged if it was forced to close.