The Ring of Brodgar is surrounded by four great mounds: Salt Knowe, Plumcake Knowe, Fresh Knowe and South Knowe. All were investigated in the nineteenth century but only one, Plumcake Knowe, contained remains. They were a part of the prehistoric landscape, but we cannot be sure of their significance. There were once other, Bronze Age, mounds around the Ring, but these have since disappeared.
The view from Salt Knowe mound: