SerpApi.Org
A series of "remarkable" archaeological discoveries - which experts say could rewrite Britain's prehistory - were discovered "by accident" on a family holiday.
John Bolton, an archaeologist, was visiting the 11th Century Pembroke Castle in 2010 when he heard there was a cave beneath it.
His interest grew when he discovered that the cave, known as Wogan Cavern, showed little signs of previous excavation - so he "badgered" Dr Rob Dinnis, from the University of Aberdeen, to take a look.
Small digs have since uncovered "extremely rare" evidence of early humans and animals - including the bones of a hippopotamus which roamed Wales 120,000 years ago.
The University of Aberdeen will now lead a larger five-year exploration of the site, which archaeologists hope could reveal "a great deal about our early prehistoric forebears".
"It was by accident really," said Bolton, who described the cave as "huge" and "unlike any other" he had seen in the UK in terms of its archaeological potential.
"[I] saw the castle, and then heard that there was a cave under it, so that automatically piqued my interest.
"I noticed, very low down, there was an old calcite floor. So it suggested that, if anything had been removed in the past, it was very little."
Bolton then visited Tenby museum and noticed that there was a small collection of stone tools from the cave.
"I thought, if that's here, [then] the paleolithic - which we're very interested in - might be deeper.
"I badgered Rob for many, many years. A few years later, he relented, and we found the time to come down and have a little look."
Wogan Cavern was thought to have been dug out by the Victorians, and it was long assumed that there was little archaeological material left at the site.
But small excavations between 2021 and 2024, brought on by Bolton's chance visit to the cavern, uncovered evidence of both humans and animals over more than 120,000 years.
Dinnis, who directed the initial digs and will lead the new excavation project, said many caves were "emptied out" during the 1800s, and so "to find one where we have quite a lot still in place, not excavated out, is completely unique".
"All of that information or most of that information [from sites excavated in the Victorian era] has been lost," said Dinnis.
"Here, we have the ability, to be able to get things like DNA from bones, even from the sediment itself, to see who was here, what they are doing and when they are doing it.
"There aren't caves like this, it just doesn't happen."
Dr Jonquil Mogg of Pembroke Castle Trust, said: "So much of it seems to be intact, it's just completely mind-blowing.
"What is found here, could unlock a deeper understanding of previous discoveries, changing what we know about Britain's prehistory.
"We can now even start to use the things that we learn here, to understand things that have been lost for other sites."
The remains of the 120,000-year-old hippopotamus at the site indicates that a record dating back to before the last Ice Age is present at the site.
This has scientific importance, as it reveals what animal species did through climatic variations and how humans responded to changing environments.
"That is why the hippo is cool," added Mogg.
Pembroke Castle Trust said the finds from Wogan Cavern would be curated and kept in Pembroke, securing the collection for the people of Pembroke, Wales and beyond.
