Garlieston was built on a drawing board long before the war ever needed it. In the mid 18th century Lord Garlies, later 6th Earl of Galloway, laid out a planned coastal village along Georgian lines on the edge of his family seat, Galloway House. The neat crescents that still curve around the bay date from this period. When the great house went up, the existing residents of the nearby settlement of Carswell were moved to Garlieston, a small, blunt act of estate-making that nonetheless gave the village its bones. By the 19th century the port was the main goods-entry for the whole Machars peninsula, and in 1876 the Wigtownshire Railway reached the harbour. Shipbuilding and shipping briefly thrummed along the quay.

Then came the war, and the secret. Prototypes of three Mulberry Harbour designs were trialled in Garlieston Harbour and at nearby Rigg Bay and Portyerrock. Engineers floated vast concrete caissons, code-named Phoenix, Hippo and other unlovely names; they tested floating roadways supported by hollow concrete pontoons called Beetles. The whole point of the system was that you could not capture a Channel port intact, so you had to bring one with you. For two years, villagers watched extraordinary objects drift in their bay and asked no questions, because asking questions in 1943 was dangerous work. After D-Day, the Mulberries were sunk into place off Arromanches and Omaha Beach. The concrete giants Garlieston had grown used to went on to land more than two million men, half a million vehicles, and four million tonnes of supplies.

One reminder of the secret war stayed in Garlieston long after the soldiers left. A concrete Hippo caisson sat in Cruggleton Bay for decades, half-submerged, photographed by curious holidaymakers. A storm finally broke it apart on Sunday 12 March 2006. The Beetles, the floating-roadway supports, have proved tougher. Their pale concrete shapes still lie at Eggerness, Portyerrock and Rigg Bay, scheduled by Historic Scotland as national monuments. To walk past them on a low tide is to step into a museum without a roof, where the artefacts are as big as buses and the labels are written in salt.

The bustle ebbed away. Garlieston railway station closed in 1964, and most of the port industry that had defined the village for two centuries faded out. Today the place is quiet in the particular Galloway way, all whitewashed crescents and gulls and the slow tick of weather. Galloway House Gardens and the path along the bay are the main reasons strangers stop here. Charles Gordon McClure, better known by his pen name Dyke White, the cartoonist who lived from 1885 to 1933, came from this village, but most visitors come for the air, the views over Wigtown Bay and the strange knowledge that the great engineering miracle of 1944 began on this small Scottish shore.