On my last day in Prague, I took a day trip to Kutna Hora to visit the Sedlec Ossuary. The story goes that the church found itself with the skeletal remains of some 40,000 people on its hands. In 1870, a woodworker was hired to handle the situation. The result is nothing short of spectacular.
Some of the bones are neatly stacked.
There is a skeletal coat of arms.
Everything is decorated with bones. Here is some of the ceiling decoration.
Perhaps most impressive is the bone chandelier, which allegedly contains every bone in the body (I did not attempt to verify this.)