Broch of Mousa, Shetland Islands The construction of Alban “brochs” as early as 100 BC and all the other substantial archeological data available such as Cladh Chiaran in Ardnamurchan, Skara Brae in Orkney, Bosta House in Lewis and Machrie Moor Stone Circle in Arran, clearly show a society no less advanced and considerably more successful against the Romans than the Britons were. Brochs were round stone towers with an internal diameter of between twenty-five and forty feet.