The beach fort of Tenby

Rising out of the sea in Tenby, St Catherine’s Island is formed from a limestone outcrop about 25m (82ft) high, on the Pembrokeshire coast. Our homepage image shows the scene at low tide, when the island can be reached by foot across Castle Beach. Riddled with small caves, for centuries this tiny island was home only to a small chapel dedicated to St Catherine and, reportedly, some sure-footed sheep. But fears of a naval invasion from France, under its first president Emperor Napoleon III, saw plans drawn up for a series of forts along this stretch of the Welsh coast in the late 1850s.
© David Clapp/Alamy