Sedlec Ossuary
It’s a small Catholic chapel, located under the Cemetery Church of All Saints. It is estimated to contain the skeletons of about 40,000 people, whose bones have, in many cases, been artistically arranged to form decorations and furnishings for the chapel.
There is a huge chandelier, which contains at least one of every bone in the human body. It hangs from the center with garlands of skulls draping the vault. The chapel is surrounded by graves of people from 1800s. You will finish a thorough visit of this church in about 15-20 mins.