I'm currently reading Peter Ackroyd's London: The Biography (well in all honesty I've been reading it for quite a while now as it's huge and far too big to take on planes). It's amazing and reflects a lot of my feelings for London. I agree wholeheartedly with what was said here. Ackroyd makes the way that the city has grown organically his central tenet and somewhere he talks about using buildings to navigate our way around the city becuase the original landmarks of hills and rivers are now gone or covered over (like the Fleet).
Well anyway, recently whilst travelling on my favorite bus (Route 19), I was shocked to notice that coming up Sloane Street towards Harvey Nicks, you can actually see Hyde Park now. The huge horrible building that used to be there has been ripped down. It completely changed my perspective on where I was and what is more interesting it completely changed my perspective on the building next to it on the right which was now shown in radically different light. It's the Mandarin Oriental London. I know see that it was a much more graceful and well thought through building than I ever realised.
It has an arch between the back and front:
And if you look at this image (which I got here), then you can see how demolishing what is outlined in green would completely change the whole area.
Just another way in which the things that are around us and how we perceive create structures of meaning. What will that corner of Knightsbridge "mean" when it looks like this: 
rather than this:
