On a crisp spring evening along the sheltered waters of Clew Bay, on Ireland’s Atlantic-facing west coast, the sea recedes as the sky deepens to indigo.
At the narrow tidal channel between the mainland of County Mayo and the small island of Collanmore Island, a pair of massive ramparts—once hidden beneath seaweed and drowned by the tide—are gently revealed, as though the living earth is drawing breath and exhaling its ancient secret.
That moment, when the sea pulls back its cloak, is where our story begins.
A Fort Lost To Sea And Time
Local seaweed cutters and sailing-club volunteers had long glimpsed odd alignments of stone at the edge of the isthmus between Collanmore and the mainland.
But it took a remarkably low tide—and a sharp-eyed archaeologist—to realise those alignments were defensive ramparts, fashioned in the Late Bronze Age and forgotten by centuries of rising water and drifting sand.
Leading the discovery is Michael Gibbons, an archaeologist whose survey team from Connemara and Mayo County Council noted that “we were lucky on the day as there were men cutting seaweed in the same area,” he told reporters.
The ramparts are faced with large limestone blocks, stretching approximately 200–300 metres across the tidal causeway, and date to around 1100–900 BC.
In a dramatic twist of geography, the fort sits where the sea now washes and hides it—yet, in its day, the land was different: the isthmus would not have been always underwater, sea levels were lower, and the locale offered both vantage and defence.
Defence And Design: How The Ramparts Worked
Picture a narrow stretch of land extending boldly into the restless sea, shaped by human hands thousands of years ago. The ancient builders understood the strength of the tides and crafted the surrounding waters into a natural defense.
Two great stone embankments—one positioned toward the mainland, the other facing the island—spanned the causeway like sentinels of stone. Their placement funneled any approach into a single, guarded route, turning geography itself into protection.
This deliberate engineering reveals a people who saw the landscape not as a barrier but as an ally in safeguarding their island home.
This pattern echoes other late Bronze Age fortifications along Ireland’s western seaboard—on lakes, headlands and islands—where communities built defensive systems in terrain that was partially submerged at high tides or vulnerable to attack by sea. The scale of the construction suggests the site was of major strategic importance in its time.
A Moment When The Sea Reveals The Past
On the day the ramparts were surveyed, the seaweed-covered walls rose from shallow water. The larger wall nearer the island stretches about 250 metres; the nearer one about 180 metres. Under normal conditions they are submerged, hidden to all but the sharpest eye. Local inhabitants knew of a rough stone alignment—but not its origin or magnitude.
The scene is cinematic: as the tide recedes, shining blocks of limestone glint pale gold in late afternoon light; the seaweed trails ripple in the tidal flow; gulls wheel overhead. A kind of moment of revelation—when the living landscape lets you glimpse the deep-time architecture of human courage and strategy.
Why The Find Matters
Firstly, it expands our understanding of the Bronze Age world in Ireland. The built ramparts challenge assumptions: not all ancient defence systems were high on hills overlooking fields—they could be coastal, built to command sea and land alike.
Secondly, this discovery serves as a poignant reminder of how much of our shared history rests quietly beneath the shifting boundaries of land and sea. Along coastlines, tidal flats, and marshlands, the remnants of once-thriving communities have been buried by time and tide.
As sea levels rose and sands drifted, the physical traces of human endeavor were gradually submerged, preserving stories of resilience, adaptation, and ingenuity beneath the waves.
Each new finding in these intertidal landscapes offers a glimpse into how our ancestors lived in harmony with nature’s changing rhythm.
Thirdly, and perhaps most beautifully for our time: the discovery invites us to pause and consider continuity. We stand on land shaped by our ancestors; beneath our tides lie the traces of their vision.
Human Echoes From 3,000 Years Ago
One can imagine young Bronze Age residents of Collanmore: women weaving flax, children gazing out at sail-shaped clouds across Clew Bay; the ramparts rising as both protection and symbol. Perhaps someone stood here, listening to waves and wind, aware of change in the seasons—and yet believing in permanence.
Today, when seaweed cutters pull on boots to harvest kelp and sailors chart the bay, they tread ground touched by those ancient hands. When we glimpse the ramparts, we connect across millennia.
A Hopeful Horizon
This discovery should not merely remind us of what was lost—it should inspire what may still be found. Coastal archaeology, once hidden beneath salt and silt, now yields its secrets. Each retrieval is an affirmation: humans create, adapt, endure.
In Ireland’s west, in Clew Bay, the sea has drawn back from its usual cloak and shown us something of its buried memory. It is a moment of wonder, yes—but it is also a moment of connection.
Because when we listen to the walls of limestone glimpsed at low tide, we hear more than stone—we hear human ambition, adaptation, hope. The past, like the tide, retreats and returns—but every time it does, we have a chance to discover, to learn, and to carry ahead.
