Hidden beneath the ancient stones of Pembroke Castle in Pembrokeshire, Wales, a vast and mysterious cave is rewriting the story of Britain’s earliest inhabitants. Known as Wogan Cavern, this enormous subterranean chamber—measuring 23 meters (75 feet) in length and soaring up to 10 meters (32 feet) high—has long been shrouded in legend and, until recently, overlooked by archaeologists who assumed it had been stripped of secrets by Victorian diggers. But recent discoveries have turned that assumption on its head, as a series of small excavations between 2021 and 2024 have revealed a treasure trove of prehistoric remains, some of which are so rare that experts say the site is unlike anything else in Britain.
According to BBC News, the cave has yielded “extremely rare evidence of early humans and animals,” including the bones of a hippopotamus that once roamed Wales some 120,000 years ago—a time when the climate was warm enough to support such exotic creatures. Alongside the hippo remains, archaeologists have uncovered bones of mammoth, woolly rhinoceros, reindeer, and wild horse, as well as stone tools and other artifacts that point to repeated human occupation over more than 100,000 years. These finds, preserved in the cave’s sediment layers, are providing a remarkable window into Britain’s deep past.
“Despite the limited work done so far, we can already say that Wogan Cavern is a truly remarkable site,” said Dr. Rob Dinnis of the University of Aberdeen, who directed the initial excavations and will lead a newly announced five-year project to explore the cave in detail. “Not only is there extremely rare evidence for early Homo sapiens, there are also hints at even earlier human occupation, probably by Neanderthals. There is no other site like it in Britain – it is a once in a lifetime discovery.” (BBC News, Nation.Cymru, WalesOnline)
The excitement among researchers is palpable. Dr. Dinnis and his team believe that Wogan Cavern has the potential to chart a long, unbroken sequence of human activity, stretching from hunter-gatherers living there immediately after the last Ice Age—around 11,500 years ago—back to Britain’s earliest Homo sapiens between 45,000 and 35,000 years ago, and possibly even earlier traces left by Neanderthals. The discovery of hippopotamus bones, likely dating to the last interglacial period, provides a vivid reminder of how dramatically Britain’s climate and environment have changed over millennia, and how prehistoric people adapted to these shifts.
“We are optimistic that the cave can chart a long sequence of human activity, from hunter-gatherers living there immediately after the last Ice Age around 11,500 years ago, back to Britain’s earliest Homo sapiens between 45,000 and 35,000 years ago, and maybe also earlier traces likely left by Neanderthals,” Dr. Dinnis explained in an interview with Nation.Cymru. “We have also found hippo bones, which probably date to the last interglacial period, around 120,000 years ago. The site could therefore tell us about how multiple changes in climate and environment affected people living there over 100,000 years or more.”
Wogan Cavern is accessed via a spiral staircase from within the castle—a castle that itself is steeped in history as the birthplace of Henry Tudor and a magnet for tourists. For years, the cave was thought to have been emptied of archaeological material by Victorian-era explorers, but the recent small-scale digs have revealed that much of its sediment and its secrets remain intact. These discoveries are not only changing the way historians and archaeologists view Pembroke Castle, but also how they understand the broader sweep of Britain’s prehistoric past.
The University of Aberdeen’s new excavation project, which begins at the end of May 2026, is being supported by the Pembroke Castle Trust and has received funding from the Calleva Foundation. The project will employ a suite of advanced scientific techniques, including high-resolution dating and the analysis of ancient DNA preserved in both bones and cave sediments. Professor Kate Britton, a specialist in archaeological science at the University of Aberdeen, highlighted the significance of the well-preserved material: “Because the bones are well preserved, we can learn a lot about past environments and ecosystems, and do high-resolution scientific dating. Pilot studies have shown that ancient DNA is preserved, in both the bones and the cave sediments.” (Nation.Cymru)
The Pembroke Castle Trust is not only supporting the scientific work but is also expanding its team and facilities to ensure that discoveries from the cavern are curated and displayed locally. Dr. Jonquil Mogg, collections manager at the castle, emphasized the importance of the finds: “Pembroke Castle has long been a very important part of Welsh and British history. Wogan Cavern has the potential to also establish it as a place of huge significance to British archaeology.”
The enthusiasm is shared by those who manage and care for Pembroke Castle. Jon Williams, the castle’s manager, expressed his excitement: “This is incredibly exciting news for everyone at the castle. We have watched with great interest as Wogan Cavern has started to reveal its secrets – it’s very different from the medieval history we usually deal with at the castle. We are thrilled that work on this wonderful cave will continue and look forward to securing the collection for the people of Pembroke, Wales and beyond.” (WalesOnline)
The upcoming five-year excavation is expected to shed light on how prehistoric people coped with dramatic shifts in climate, from the icy tundras of the last Ice Age to the warmer, more verdant periods when hippos and other now-vanished animals roamed the landscape. The project will also help clarify the timeline of human occupation in Britain, potentially revealing new information about the arrival and coexistence of different human species, including Neanderthals and early Homo sapiens.
For Pembroke Castle, already a site of national importance, the discoveries in Wogan Cavern mark the beginning of a new chapter—one that reaches far beyond the medieval era and deep into the mists of prehistory. As the new excavations get underway, archaeologists and historians alike are eager to see what further secrets the cave will yield. The hope is that Wogan Cavern will not only enrich our understanding of Britain’s ancient past but also inspire new generations to appreciate the depth and diversity of the island’s human story.
As the first shovels break ground at the end of May, all eyes will be on Pembroke—and on the extraordinary cavern beneath its castle walls—waiting to see just how much of Britain’s prehistory can be rewritten from the darkness below.