Year in which the first building in the lot still existing at the begining of 2013 was built

Here we are, in Madrid, capital of a vanished empire, a city in the old world. And this central area has a built stock that is probably younger than that parts of downtown Mannhattan, which in some parts is quite a historic district on its own right (only with much taller buildings, but aging ones after all). Sure, this is a XIXth century extension, but it is a proof that, despite what many could think from abroad, european cities are far from being static coocoons preserving old glories. Just note, as I have mentioned before, that this map results from the use of cadastral data, so in some cases (perharps 10%) building ages are not what you would asume, as the cadastre re-start the age of a building when it undergoes a massive refurbishment (I know some that would like that after a surgery…)