If you're in London for some time, I'd definitely ...

If you're in London for some time, I'd definitely recommend going up it! The London eye gives a great view of the city in all directions on both sides of the river, and it lasts for at least a solid 15 minutes. There is a long line, however, because this is one of the most visited attractions in London. If you're visiting, make sure you come with enough time if you also want to visit other places.