Whether or not you enjoy an intimate audience with Karl Marx (see previous commentator), Highgate cemetery is one of London's true treasure troves. To appreciate its full splendour, you have to cross the road and visit the old section, the part with the magnificent Victorian facade, accessed on the hour every hour (or something like that). Inside, you'll find narrow dirt tracks navigating their way between tangled vine and stone, all green and grey and wet and fungified. The catacombs, a kind of sunken garden of vaulted tombs, are unexpected and hauntingly beautiful; they alone are worth the visit, worth the wait (should you arrive on the half-hour) and well worth the disturbing spectacle of visitors humping Marxies headstone...

...who shagged on Karl Marx's grave. I know loads of people want to do that. I know someone who did.