From the Early Neolithic farm at Knap of Howar to the flamboyant chapel built by Italian prisoners of war in the 1940s, the Orkney Islands are amazingly rich in historic and prehistoric sites. At their centre is a cluster of spectacular Neolithic monuments - domestic, ceremonial and burial - now inscribed as a UNESCO World Heritage Site. Orkney later became a flourishing Norse centre, with St Magnus Cathedral in Kirkwall as its striking centrepiece. The palaces of the notorious Stewart earls also survive as a relic of Renaissance grandeur; while later periods have left evidence of...