In 1929, Australian geologist Paul Hossfeld stumbled upon a partial human skull in a mangrove outside the coastal town of Aitape in Papua New Guinea. Originally thought to belong to Homo erectus, the skull was subsequently dated to the mid-Holocene period, about 6,000 years ago. Now, new research suggests the bone fragment belongs to the world’s oldest known tsunami victim—an important piece in the conversation about how modern populations can adapt to rising sea levels.