10 Most Mysterious Buildings in the World

Known as the “Bone Church,” the Sedlec Ossuary in Kutná Hora contains the skeletal remains of an estimated 40,000 to 70,000 people. These bones aren’t just stored—they’re arranged into elaborate decorations, including a chandelier made entirely of human remains. Originally built to house remains displaced by war and plague, the ossuary’s morbid yet artistic interior poses questions about death, ritual, and spiritual symbolism. It remains one of the most unusual—and haunting—sacred spaces in Europe.