London Eye

It was built to mark the year 2000 and was meant to be temporary, but it stayed. It is 135 metres high with 32 glass capsules, one for each London borough, numbered 1 to 33 because 13 is skipped. A full turn takes about 30 minutes and the wheel never stops: you board while it moves.

From the top on a clear day you can see about 40 kilometres: Parliament right below, Buckingham Palace, St Paul's, the City and, in the distance, Windsor Castle.