GeoGraph - photograph every grid square

"The Brehon Tower (Fort Brehon) is accessible only by boat and sits on Brehon Rock, an islet in Little Russell Channel between St Peter Port and the islands of Herm & Jethou. Thomas Charles de Putron (1806-1869) built the oval tower with Herm granite, completing the work in 1857.
Although not strictly a Martello tower, Brehon represents the final evolution of the basic design of the Martello tower. In 1914 the War Office transferred ownership of Brehon Tower to the States of Guernsey. During the German Occupation of the Channel Islands, an anti-aircraft gun was placed on the tower. Today, although the site is open to visitors, the tower is closed. The tower holds a light operated by the Guernsey Harbour Authority. The island is home to a breeding colony of common terns".
Seen from the Herm-St Peter Port ferry.
Link