This is a church in Sedlec (a little village outside Prague). The story is a knight went to the holy land during the Crusades and returned with some holy dirt. He sprinkled it outside the church. It became prime real estate for the departed. Big gold coins if you want a place in the holy graveyard. So the places filled up fast. Then the plague came and lots and lots of people died. There were too many bones from the dead. So later a wee monk dug up the bones. He mades nice decorations of all the bones in the church. More room. And art. Ah glorious art. So white and pure. Holy robes indeed.