Barrière de fer
Fort de Villers was built following the Franco-Prussian War to defend Paris. Located to the east of Paris in Villiers-sur-Marne, the fort was part of an outer ring of eighteen major fortifications built in response to improvements in the range and effectiveness of artillery since the construction of the Thiers fortifications of the 1840s. It was built in accordance with improved principles of fortification developed for the Séré de Rivières system.