The Sedlec Ossuary located in the Czech Republic is estimated to contain the skeletons of 40,000 – 70,000 people that likely died in the black plague.
When the church was built around 1400 in the middle of the Sedlec Cemetery many bodies had to be exhumed or displaced to make room for the church and new burials. The Monks started stacking the bones in the church.
Finally in 1870 a woodcarver began using the heaps of bones in a decorative manner leading to its glorious and macabre appearance today!