Thanks dear Shemiran. I had not heard of this church before!

Much more on the history of the Bone Church:

"Why?

Urban myth has it that a monk went mad and made things from the bones, and there are stories to suggest that partially blind monks entrusted with the care of the chapel were the first to begin piling the bones into geometric shapes.

The decorations and sculptures were created though by a woodcarver named František Rint. In 1870, he was commissioned by the landowners of the time, the Schwarzenberg family, to decorate the chapel with the bones and create a reminder of the impermanence of human life and inescapable death."

http://www.outsideprague.com/kutna_hora/bone_church.html