In Kutná Hora, Czech Republic—once the only royal city after Prague—stands a chilling yet world-renowned cathedral: the Kostnice. In 1318, the Black Death swept across Europe, and the Czech lands, deeply affected, suffered immense losses, with over thirty thousand people buried locally in just one year. During the Hussite Wars of the 15th century, tens of thousands of innocent lives were brutally taken, churches and monasteries were burned or demolished, and many monks fled here, unearthing bones to construct this largest ossuary in the world. It serves both as a church and a tomb, with over seventy thousand skeletons forming this rare architectural marvel. 　　The dead stand in every corner of the cathedral, their hollow eye sockets gazing at visitors from around the world. You look at them, and they look back at you—the boundary between life and death blurs...