Fort de Six-Fours, Military fortress in Six-Fours-les-Plages, France.

Fort de Six-Fours is a military fortress on a hilltop about 200 meters above sea level, featuring an irregular pentagon shape with nine cannon batteries facing seaward. The structure combines land and coastal defense through its placement and thick limestone walls reinforced with brick construction.

After the Franco-Prussian War of 1870, the Navy bought the old fortified village of Six-Fours, expropriated its last inhabitants and demolished the houses, the church of Sainte-Marie de Cortine and the castle. Construction of the fort began in 1875. In 1943-44 the Wehrmacht's 355 Flak-Abteilung armed it with four 88 mm guns; it surrendered on 26 August, and a squad of spahis took 490 prisoners.

The fort's name comes from the commune of Six-Fours-les-Plages, not from towers. The site replaced the old fortified village whose castle and church of Sainte-Marie de Cortine were razed before construction began in 1875. Today the Navy runs it like a warship: a bell rings and loudspeakers announce "Le commandant monte à bord!" when the commander arrives.

The site remains an active French Navy communications facility and cannot be fully accessed, but several viewpoints surround the area for viewing. These overlooks provide good sightlines toward Toulon's harbor and the mountains beyond.

Inside the fort is a six-meter ammunition lift system and original bread ovens from its operating period as an active military installation. These working elements reveal how soldiers lived and conducted daily operations within the fortified walls.