Located on the South Bank of the Thames River in London, the London Eye is a 135 m high Ferris wheel which was erected in 1999 and was at the time, the tallest in the world. Three other Ferris wheels have held that qualification since, and today the London Eye is the fourth-tallest in the world and still the tallest in Europe. With over 3.75 million visitors annually, it is the most popular paid tourist attraction in the UK.