Built as an artillery fortress between 1541 and 1544 by Henry VIII to stand guard over the Solent Sea and protect the key naval base at Portsmouth, Hurst Castle was once a symbol of the UK's strength.
But last year it began to crumble, weakened by the elements, it is now confronting a more modern danger - the changing climate.
The full force of ever-strengthening storms and stronger waves crashing closer to its foundations is making this historic site hard to protect. The sea, once several hundred meters away, is now lapping at the castle walls.
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It has been placed on the World Monument watch list, making it one of the 25 most important sites at risk worldwide.
In February 2021, a section of the east wing of Hurst castle collapsed into the sea after a storm. Emergency work stabilized the building and 22 tons of rock were brought in to create a sea barrier, in the hope of preventing further damage.
The full repair of Hurst castle could cost tens of billions of dollars. /Kitty Logan /CGTN
Today, blocks from the crumbled castle wall and parts of ancient gun turrets salvaged from the sea are still piled up on the beach in fenced-off storage.
Several historic sites at risk
The full repair could cost tens of millions of dollars and so English Heritage, the charity which oversees this historic building, is urgently seeking to raise more funds to save it.
"What we've had to do since then is underpin the collapsed section, remove all the fallen debris, and redefine the coastline," says Rob Woodside, the Director of Estates at English Heritage. "And we spent around £3 million ($3.35 million) making sure it's sound and protected, but that doesn't include rebuilding the whole thing."
The might of nature is putting several other historic sites at risk too.
English Heritage says the impact of climate change is now threatening at least six of the coastal historic sites it manages./Kitty Logan/CGTN
The 13th Century Tintagel Castle in Cornwall, linked to the legend of King Arthur, is also being battered by winds and struggling with erosion as the surrounding cliffs crumble. English Heritage says the impact of climate change is now threatening at least six of the historic coastal sites it manages.
'Vulnerable to a changing environment'
"Coastal erosion is nothing new. It's a natural process and we always expect it around the coast of England," says Woodside.
"But we're concerned that we're seeing increasing sea level rises and storm events which may be connected to climate change. So, we're recognizing the sites we're looking after are increasingly exposed and vulnerable to a changing environment."
The charity is concerned that at some sites, such as Hurst Castle, fending off the elements may eventually prove impossible. The narrow spit of shingle beach the castle sits on is also the last line of defense for the land beyond it, protecting a small fishing harbor and salt marshes hosting rare birds. But this entire low-lying area is now vulnerable to sea level rise, which experts predict could be as much as a meter within a hundred years.
"I'm very confident we can act now to look after them for this generation. What I'm concerned about is what happens in the future. Our job now is to do our best to make sure they're well maintained that we update all the existing coastal defenses," says Woodside.
But the fears are that if the current climate trends continue, Hurst Castle could one day succumb to the sea, changing the surrounding landscape forever.