The Fort de Tournoux is a fortification complex in the Ubaye Valley in the French Alps. It was built between 1843 and the early 20th century to defend France against invasion from Italy and Savoy. It was described as the "Military Versailles of the 19th century," resembling a Tibetan monastery on the mountainside above the Ubaye. The fort is actually an ensemble of fortifications, including some "batteries" that rival the main fort in size and power.