Many years ago I helped on of my acquaintances who is an artist with Czech translation on the Bone churches of Bohemia. At that time he had a theme which was has to do with macabre arts for some Halloween production and I introduced him into this heritage of medieval Europe. Sedlec ossuary appeared in several movies like Dungeon and Dragons. In the peak of the medieval times, there were at least 250 of these Bone churches in Kingdom of Bohemia alone, from which 1/4 survived until today. I have not feel anything negative by visiting these sites. I actually find them peaceful. It also tells me that JW beliefs on resurrection is all BS. All these million of people lived, had dreams, and died, and nothing is left of them than bones. There won't be any earthly resurrection, Earth cannot accommodate all these people (about 90 billions). JWs are afraid of these places, because it will reveal how deficient is the system of beliefs, especially dealing with death.
Evora in Portugal, Kudowa in Poland, or Milano are known for its Bone Churches. There are probably hundreds of more around Europe, forgotten and hidden from public eye. If sex was a taboo in 18th and especially in 19th century, the death is the taboo of the 21st century. Skulls and bones are not demonic nor has nothing to do with occultism. It is one of the made-up WT things to control its members.