Fifteen miles south of Lerwick, the scattered crofting communities of Sandwick look across to the Isle of Mousa, site of the best-preserved broch in Scotland. This fortified tower was built around 2,000 years ago and still stands close to its original height of 45 ft. It's a very impressive structure when you see it from the inside and has chambers, galleries, an internal staircase and a parapet. The broch features in a Viking saga of the 12th century when the mother of Harald, Earl of Orkney, took refuge there with her lover. Mousa island is also home to many seabirds and waders, most notably the Storm Petrel, which is best seen at dusk as they return to their nests amongst the beach rocks. Tourists can also see seals on the white-sand beach at West Voe.