I like to think that, as a Londoner, I know a few things about my home city. Not much, just the regular tourist info, plus a few esoteric tidbits. But today I was gobsmacked to find out a couple of new things.
First of all, that one of the World War II 'Deep Level' shelters is round the corner from where I live. Quick history check: in the air-raids, most Londoners sheltered in the London Underground, but there were also 6 'Deep Level' shelters built that had space for thousands of people and were, as you might have guessed, much deeper than regular underground stations, therefore much safer (though I bet they were hot and uncomfortable).
And there's one of these super-shelters round the corner, hidden in a Marks & Spencer car park. I doubt it was an M&S car park during the war, but who knows.
Then, almost in the same breath I found out about 'Paddock' - the top secret war rooms under Dollis Hill that were designed to be the last-resort command centre for Churchill and his Cabinet. (Because the well-known war rooms in Whitehall would have been destroyed by a direct hit.)
Churchill apparently only went there once, and didn't like it. Too damp, and there were no toilets. That's right - a quarter of a million pounds (equivalent to about £80 million today) on an emergency centre of government from which to fight for the future of the free world, and the architect forgot to put in a toilet.