A view from one of the gondolas of the British Airways London Eye as the sun sets. The wheel gives a panoramic view of London, rising to 450 ft above the Thames. Photograph: Toby Melville/PA
This City now doth like a garment wear The beauty of the morning; silent, bare, Ships, towers, domes, theatres, and temples lie Open unto the fields, and to the sky; All bright and glittering in the smokeless air
William Wordsworth
It was a bad start to the journey. After buying a return ticket to Westminster at Blackfriars Tube station and passing through the electronic ticket barrier, the sign at the bottom of the stairs said: "Westminster station closed."
It wasn't a catastrophe. But as the ticket inspector handed me back my £3 fare, I wondered whether she might have mentioned it earlier.
A few minutes later, sitting in the back of a taxi as it sped along the Embankment, I was rather pleased not to have been squashed into a Tube carriage. Tracing the curve of the Thames as it flowed westward, the grey light of a London afternoon cast a beautiful, melancholy glow over the city. Westminster and the offices of the British government were ahead of us and St Paul's Cathedral was left behind.
Just as we turned into another bend of the river and looked across to the other side, I got my first glimpse of the largest observation wheel in the world hovering tantalisingly over the brown water.
For months Londoners and visitors to London have glimpsed parts of this huge feat of engineering from the back seats of taxis or on buses as they've crossed the bridges on the Thames. Up close, the British Airways London Eye dominates the skyline. It dwarfs the buildings huddled around it and, if people survive the thrill of being suspended 450 ft above the river in a glass-panelled capsule, the Eye could be there for a long time.
Once I had joined a group of colleagues outside the Eye's ticket office at the old County Hall building opposite Westminster, we couldn't help but look up at the hundreds of feet of grinding, curving metal moving slowly above our heads. And standing next to the wheel's giant legs, it was impossible not to think of the mythological figure of Colossus straddling the sea.
The countdown began and hearts were beating faster. Jamie Bowden, an energetic British Airways spokesman, gave a wellrehearsed pep talk to a slightly wary group of journalists. He reeled off a few facts - the wheel could withstand wind speeds up to 20m/sec - and everyone felt calm.
But then he blew it. He calmly assured us the fire brigade could get everyone off the wheel within eight minutes if a "catastrophic series of events", such as a helicopter flying into the centre of the wheel, caused it to fail. A few people looked worried.
But we had come this far so we queued up, had our photos taken in what looked like a garden shed and carried on staring up at a truly amazing machine.
Stepping on board the glass capsules was the trickiest part. The capsule moves slowly, but you feel that if you miss the jump you could end up in the Thames. Of course there's little real chance of it happening - there's a net underneath the "docking platform" - but it was a strange feeling to step out with the brown river swirling underfoot.
Once inside, the gentle upward movement was so smooth that many people asked whether the capsule was moving at all. It was, and soon the tourist-map square-mile of London gave way to an extraordinarily beautiful, chaotic city.
The people below became dots on the ground and buses were reduced to small red boxes scuttling across the city.
As the capsule rose into the air, Battersea power station, looking like a magical castle on the river, fell away into the distance. To the right, and what felt like a very long way below the capsule, was the Telecom Tower, St Paul's Cathedral and the Tower of London.
We were told that when Londoners travelled on the wheel the first thing they looked out for during the 30-minute journey was their house.
I couldn't see my house - north-east London was shrouded in mist - but what a joy to see the church spires on the hills of Hampstead, the highest point in London, peeking out from behind low grey clouds.
Right at the very top of the Eye the Millennium Dome, London's other symbol of the year 2000, peeped out from behind Tower Bridge. It looked small and squat, "trying to be all things to all men", as the London Evening Standard once said. Meanwhile we soared above the city, utterly graceful where the Dome appeared disorganised.
Modern travellers are spoiled by the fact that they can fly over cities in jumbo jets and look down on the streets below. I've seen London a hundred times from the air so I knew I wasn't going to see something new. But somehow the sense of freedom rising above the city in a glass capsule owed more to the end sequence of Roald Dahl's Charlie and the Chocolate Factory than being strapped into a tiny seat on board a plane.
If you can imagine looking down over the city from the highest point of the wheel at 450 ft and not feel sick, childhood memories of fairground ferris wheels and coloured lights await. Only this time if you open your eyes, the view is even better.