The London Eye is celebrating its tenth birthday. It was put up in 1999 as a mark of the 2000 Millennium.
At 135m tall, it's the biggest ferris wheel in Europe, and it's the most paid for tourist destination in the UK.
There are 32 egg-shaped domes attached to the wheel, one for every London borough, and each one can fit up to 25 people.
The wheel doesn't even have to stop to let people on and on because it goes around so slowly - it takes over half an hour to go around once!
There have been more than 3,000 celebrity visits in the Eye's 10 years, and EastEnders was even filmed on it when Jim asked Dot to marry him!
In its 10 years it has taken more 36 million passengers and the wheel has turned over 45,000 times.
A special light show will take place on the night of its birthday, to celebrate 10 years in existence.
You can see around 40km from the top as far as Windsor Castle on a clear day.
The London Eye isn't just a tourist attraction, it's also a place for romance as there have been 433 weddings on board!