Fascinating ... do they just have a limited amount of space for a cememtery? Is it more efficient to stack up bones in a building?
The town cemetery is small (maybe 1/4 acre) and from what I can tell Europe has had a problem with room for their buried dead for awhile.
I watched a documentary a few years back that said medieval Paris got to the point where dead bodies were spilling into basements and the graves of my German ancestors no longer exist cuz they are under the next go around. (I think grandpa gets a stone for about 30 years unless someone continues the upkeep.)
I don't think they actively use the bone house anymore but I can't remember why. I would have no problem with going back to find out!