The Millenium Wheel, also known as the London Eye, at 135 m high, is the world's tallest observation wheel and the fourth tallest structure in London. It was built to celebrate the turn of the Millenium and cost some £20 million. Offering spectacular views of the city of London it can carry 800 passengers at any one time in its 32 transparent pods. A single revolution of the wheel takes approximately 30 minutes.