One of my favourite places to snoop around is the food market open on a Thursday, Friday and Saturday. It's always bustling with crowds so great for people watching. You can get the best of anything here which is why it's hard to resist spending a small fortune.
Eccentric and surprising house and museum of architect Sir John Soane. Mostly unchanged since his death over 180 years ago, it is full of atmosphere. Also have spotlit, late night openings.
These giant spectral cylinders are great at different times of the day but my favourite time is around dusk when the buildings in the city start to light up. The Gherkin and the new Shard building are framed in the lowest ring then the shifting colours of the sky are almost split in the following ellipses.