Brownshill Portal Tomb - Tuama Ursanach Chnoc an Bhrúnaigh, is a Portal Tomb with a very large and heavy capstone estimated to weighs about 150 tons, supported by three uprights and two boulders. There is evidence of another upright nearby. It was built between 4000 and 3000 BC. The capstone, described as the heaviest of its type in Europe, is thought to have originally been covered by an earthen mound and a stone blocked the entrance.