The Fortress of Mont Agel was built between 1889 and 1892 as part of the Séré de Rivières system of fortifications. The main réduit was sited on the southwestern side of the roughly by summit plateau, overlooking Nice. It is now the site of the main facilities of Base Aérienne 943 and has been extensively altered. A barracks was located near the center of the plateau, while several batteries, designated by number, were located around the plateau, all enclosed by a wall. Battery A became the Maginot entry. Battery B has been obscured by later changes, but its underground magazine remains. Battery C mounted four 95mm guns at the middle of the east side of the plateau. Battery D was located on the southeast side of the plateau, with Battery E nearby. None of these batteries exist in their original state. In 1897 six emplacements were prepared for additional artillery, ranging from 90mm guns at positions 1 and 2 to 220mm mortars at Battery 3. Battery 4 was a prepared site for field artillery, and Battery 5 was planned for four de Bange 120mm or 155mm guns.