London Eye

They built this thing to be temporary. The London Eye was supposed to stand for just five years — a flashy millennium novelty that would be dismantled and forgotten by 2005. Instead, it became the most popular paid tourist attraction in the UK and one of the defining shapes of the London skyline. Funny how the things we don't plan to keep become the ones we can't imagine losing.

The wheel stands 135 metres tall and was, from its completion in 1999 until 2006, the tallest Ferris wheel on Earth. It carries thirty-two sealed, air-conditioned capsules — one for each of London's boroughs, though there's no capsule number thirteen, because superstition apparently outranks civic completeness. Each capsule holds twenty-five passengers and sits on motorised mounts that keep it level as the wheel rotates. A full revolution takes roughly thirty minutes.

The opening was a comedy of engineering ambition. Tony Blair ceremonially "opened" it on New Year's Eve 1999, but a capsule clutch problem meant no paying passengers rode until 9 March 2000. Getting it upright in the first place was a drama — the wheel was assembled flat on pontoons in the Thames, then slowly raised to vertical over several nail-biting days while the world watched.

On a clear day, the views stretch for forty kilometres in every direction, encompassing Windsor Castle to the west and the North Downs to the south. The Eye has carried over eighty million passengers since opening, which makes it one of the most visited structures in the world. It has also become the centrepiece of London's New Year's Eve fireworks display — proof that temporary things have a way of becoming permanent traditions.