That's a lovely photo essay. I went to the Ceremony of the Keys last year, and the warders who run the ceremony make it entertaining and interesting. Even if the OP can't make it, I'd recommend it to anyone else with the time and inclination to write a letter to the Tower.

I've been on the London Eye a few times, and enjoyed it every time (even when it was raining) - other places you can gaze over London include The Monument and the very top of St Paul's. Denis Severs' House is fascinating too, especially if you lose yourself in the atmosphere of it.

And not forgetting the current exhibition at the Natural History Museum