Discovered on the small island of Collanmore off the west coast of Ireland is a prehistoric fortress dating back to the end of the Bronze Age. Built between 1100 and 900 BCE, this fortress was created by constructing two large walls made of limestone blocks that are around 200-300 meters long. Archaeologist Michael Gibbons describes the structure as vast and covered in seaweed, making it difficult to notice until recently.
The discovery of this fortress was purely by chance, as men cutting seaweed on the isthmus connecting the island to the mainland accidentally stumbled upon it. Although one wall had been previously known to local residents, its age and significance were not recognized until now. The fortress has been compared to other Bronze Age fortifications found in Western Ireland, such as Dún Aonghasa on Inis Mór. Gibbons believes that Collanmore Island was an important center during this era, much like Dún Aonghasa’s reputation as a significant center of trade and culture.