The newly opened Mail Rail Ride in London is great. You get to spend about 20 minutes travelling on the old underground mail trains which used to speed the post around central London. There are also two fab museums, one each on either side of the road.
But for my money, the bank note information and fire extinguisher display stole the show:
No information that I saw about whether or not it’s true that it is against the law to stick a postage stamp on upside down. But luckily, I already had a blog post on that.