I went to Czech Republic in 2011 Christmas. One of the place I've visited in the country is "The Sedlec Ossuary", a small Roman Catholic chapel located beneath the Cemetery Church of All Saints (Czech: Hřbitovní kostel Všech Svatých) in Sedlec, a suburb of Kutná Hora. It is one of twelve World Heritage Sites in the Czech Republic. The ossuary is estimated to contain the skeletons of between 40,000 and 70,000 people, whose bones have, in many cases, been artistically arranged to form decorations and furnishings for the chapel.
It was fascinating and it was so inspiring that I had to put the ideal into one of the illustration for my 2012 comic creation. Photos of the sedlec ossuary below: