London is a city that is continuously evolving, I love seeing old buildings being brought back into use, and also the glimpses of the past that remain painted on odd corners.
I used to look across the river everyday at Bankside Power Station while I was at school, it was a desolate sight. It is now the Tate Modern, and people throng the tree lined walkways around it.
Another view of this landmark from Travel with Intent here.
And if you wander round the slowly gentrifying back streets of Southwark, you can still see the signs of its previous lives.