The best were a few pieces from the Japanese photographer Sohei Nishimo (I believe he's only 31, although he looks like a slightly older Victorian gentleman $-$ at least judging from the pictures on his website).
They are called Diorama maps and basically are extremely accurate city maps made by arranging in a huge puzzle several photos of the city taken while he was walking around.
This doesn't really make justice to the real thing, which is truly amazing! In the exhibition they had the Diorama maps of Manhattan, Paris and Tokyo, which are all awesome (by the way, the exhibition is until next Sunday and definitely worth catching).
After that, we went to have lunch at some friends' and, later, for a nice, long walk. Of course, I didn't go to the toilet before we left the house and, of course, just in the middle of our walk I was bursting for a pee. Marta, as usual, pointed out that I should have gone earlier, while I, as usual, protested that I (like all men) only go when I have to go, which of course means when there are no toilets around. Luckily, we managed to find a pub just in time.