Do you know about The City Of The Dead in Paris? Basically, Paris cemetaries (18th or 19th century) were so full, bodies were buried stacked on top of each other and people whose houses were next door had BODIES FALLING THROUGH THEIR BASEMENT WALLS and if it rained too hard bodies would float up because they weren't deep enough anymore. So, there are all these old tunnels under Paris from Roman times when they quarried the limestone right there and built with it (this is why in parts of Paris they cannot build any higher or the ground wouldn't support it and the buildings would cave in). So they dug up the bodies and put them in the tunnels. But they didn't just move them and line them up or make neat piles (because so many of the bones were not attached anymore and it was impossible to know who was who) ...they FUCKING MADE ART WITH THEM.

Those walls are made with human bones.