Phare de la pointe Saint-Gildas, Coastal lighthouse in Préfailles, France.

The Phare de la Pointe Saint-Gildas is a lighthouse in Préfailles, where a green metal mast and lantern rise from the flat roof of a former stone semaphore building painted white. The two-storey base has shuttered windows and a thin metal railing along its roof edge, and a lower white building with a red tiled roof adjoins it.

The site began in 1861 as a semaphore station for ship communication and coastal monitoring. During World War II, a temporary light was added using optical equipment from other French coastal stations before the current structure was built.

Since 2004 the disused semaphore, handed by the Navy to the commune of Préfailles, has been a museum space. Its displays cover the Saint-Nazaire pocket, where the German occupier held out until 11 May 1945, and the shipwrecks off the Jade Coast, among them the steamer Saint-Philibert, which sank in 1931 returning from an excursion to Noirmoutier with 500 passengers aboard.

The lighthouse has operated automatically since 1986 under remote control from Saint-Nazaire, which means there is no on-site staff. Visitors can explore the surrounding grounds and the museum housed in the adjacent building year-round.

The museum documents the sinking of the passenger ship Saint-Philibert in 1931, one of the region's most tragic maritime disasters. From this spot, visitors can take in panoramic views of the Loire estuary and Bourgneuf Bay.