In reply to goldmember:
Where is the London Stone?
(Cannon St)
What links the British Library, Clerkenwell Green and Highgate Cemetery?
(Communisim - where Marx worked, where Lenin worked - and may have met Stalin for the first time, and where Marx is buried).
What was unusual about the London Flood of 1814?
(It was a flood of beer in Tottenham Court Road. Don't laugh - eight people were killed after a brewery explosion - mostly drowned in cellars.)
When did London have it's first Indian restaurant, and it's first Indian MP?
(1810 - Sake Dean Mahomed established the Hindoostane Coffee House in George Street, central London. 1892 - Dadabhai Naoroji became MP for Finsbury Central.)
And since tube questions seem popular - which line has the most suicides?
(Northern line of course!)