Rifle rampart on the island of Värmdö

Construction of fortifications began in the 1880s. Defensive line had more than 2 kilometers length in arc around the Fort Fredriksborg. It was a kind of tête-de-pont in front of the ferry Rindö-Värmdö. The line consists of seven permanent battery caliber up to 152 mm, and chain of infantry strongpoints connected with rifle ramparts.