Fort Eben-Emael was a greatly enlarged development of the original Belgian defence works designed by General Henri Alexis Brialmont before
World War I. Even in its larger form, the fort comprised a relatively compact ensemble of gun turrets and observation posts, surrounded by a defended ditch. This was in contrast with French thinking for the contemporary
Maginot Line fortifications, which were based on the dispersed
fort palmé concept, with no clearly defined perimeter, a lesson learned from the experiences of French and Belgian forts in World War I. The new Belgian forts, while more conservative in design than the French
ouvrages, included several new features as a result of World War I experience. The gun turrets were less closely grouped. Reinforced concrete was used in place of plain mass concrete, and its placement was done with greater care to avoid weak joints between pours. Ventilation was greatly improved, including an air filtration system for protection against gas attack, magazines were deeply buried and protected, and sanitary facilities and general living arrangements for the troops were given careful attention. Eben-Emael and Battice featured 120 mm and 75 mm guns, giving the fort the ability to bombard targets across a wide area of the eastern Liège region. It was more heavily armed than any other in the PFL I. In contrast to the other forts whose main weapons were in turrets, Eben-Emael's main weapons were divided between turrets and
casemates. The 60 mm, 75 mm and 120 mm guns were made by the Fonderie Royale des Canons de Belgique (F.R.C.) in the city of Liège. The artillery turrets were so well-designed and constructed the artillerists were not required to wear hearing protection when firing the guns. • Block B.I – entrance block with two 60 mm anti-tank guns (F.R.C. Modèle 1936) and machine guns. • Blocks B.II, B.IV and B.VI – flanking casemates located around the perimeter ditch to take the ditch in enfilade with two 60 mm guns and machine guns. • Cupola Nord and Cupola Sud – each had one retractable turret with two 75 mm guns (F.R.C. Modèle 1935), • Visé I and II – each houses three 75 mm guns, facing south. • Maastricht I and II – each houses three 75 mm guns, firing north in the direction of Maastricht. • Canal Nord and Sud – were twinned blocks housing 60 mm guns and machine guns covering the canal. 'Sud' was demolished when the canal was enlarged. • 'Mi-Nord and Sud' are machine gun blocks (
mitrailleuses) in the main surface of the fort. They were crucial in defending the top of the fort. • 'Block O1' overlooks the canal and guarded the Lanaye locks. It housed a 60 mm gun and machine guns. Underground galleries extend over beneath the hill, connecting the combat blocks and serving the underground barracks, power plant, ammunition magazines and other spaces. == Personnel ==