On the steep Mediterranean cliffs of Gibraltar, archaeologists have stepped into a room that no human had seen for tens of thousands of years. Hidden behind a plug of ancient sand in Vanguard Cave, part of the Gorham’s Cave Complex, a 13-meter chamber lay sealed for roughly 40,000 years, preserving rare clues to the final chapters of Neanderthal life on a changing coastline.

For scientists, this is not just a dramatic discovery. It is a time capsule that connects deep prehistory with very current questions about sea level rise, coastal ecosystems, and how humans respond when their environment transforms around them.

Gorham’s Cave Complex sits within the Gibraltar Nature Reserve and was inscribed as a UNESCO World Heritage Site in 2016, largely because it preserves some of the last known refuges of Neanderthals in Europe. Vanguard Cave and its neighbors show evidence of Neanderthal use for roughly 100,000 years, possibly until around 28,000 years ago, later than many other sites across the continent.