If you want a peaceful day out of the busy city, Highgate doesn't really feel like London. The cemetery is interesting and peaceful, there's a tour of the old half which is definitely worth the money. Karl Marx, among others are buried there.
London has plenty of beautiful cemeteries. Brompton is one of the ‘Magnificent Seven’ and has many interesting tombs. It was also an inspiration of names for Beatrix Potter and the resting place of Emmeline Pankhurst.
When I first took up photography I knew it was something I wanted to do but was unsure of what I wanted to take photos off. I started out by mainly photographing London's graffiti and street art. Graffiti isn’t tolerated in London as much as in other cities (such as Berlin or Lisbon) but it has a long history in the capital and if you know where to look there's a lot of it around. Some of the best street artists and graffiti writers in the world either live in or travel to London to use it as a canvas. It's not something I photograph so much anymore but I still admire those who do it. The risks involved and their dedication are truly remarkable. I always wish I had the balls and the talent to try it myself.