The ossuary beneath St. Peter and Paul’s church in Mělník, Czechia filled over roughly two and a half centuries — plague dead, Thirty Years’ War soldiers, and ordinary churchyard burials, until the cemetery closed in 1775. Between 1915 and 1919 the anthropologist Jindřich Matiegka arranged some 10,000 of the bones into a pile over six feet tall, then stacked 5,000 more into a cross, a heart and a tunnel of leg bones. He signed it “Ecce mors”, spelled in skulls.