I went to a small town call Kutna Hora. There is a Sedlec Ossuary (Kostnice v Sedlci) or a small Roman Catholic chapel. This place is listed as one of the twelve World Heritage Sites in the Czech Republic.
Inside the church, it is estimated to have between 40,000 and 70,000 skeletons of people, whose bones have been artistically arranged to form decorations and furnishings for the chapel.
It's not a huge chapel, but all of the bones are kinda interesting.
There is a giant coat of arms made of bones,
skull garland lining the place,
and a giant chandelier in the center that contains at least one of every bone in the human body.
My favorite part was this cool skull on the ground outside of the chapel.
There are other cool buildings in Kutna Hora, but this was my favorite.