The blockhouse or surveillance fort of La Platte stands at an altitude of 2,000m. In the same way as the Vulmix and Le Truc forts, it formed part of the fortification system intended by the engineer Séré de Rivière. Up until World War II, a series of developments were added to upgrade it: a watch tower was built for firing and surveillance, as well as railings over 30m around the fort.Sold by the army in the 1960s, it is now a private property closed to visitors.