Belgian Fort Eben aimar is probably the largest bunker in the world. The fortress is built on a small granite plateau, 900 meters long from north to south and 700 meters wide from east to west. Its northeast and northwest are almost vertical cliffs, about 40 meters high, and the turbulent Albert Canal passes under the cliff; The south is separated by a wide anti-tank trench and a 7-meter-high protective wall. The fortress is surrounded by the so-called "canal belt" and "trench belt", with reinforced concrete bunkers, searchlights, 60 mm anti-tank guns and heavy machine guns. The Maas River to the east of the fortress is parallel to the Albert Canal, forming a peripheral obstacle.

Eben Emaer Fort is actually a group of carefully designed and built fortresses. It is modeled after the intricate fortifications of maginot line. At first glance, each fortress seems to be scattered in a pentagonal area, but in fact, it is a defense system that skillfully combines battery, rotating armored turret, anti-aircraft gun position, anti-tank gun position and heavy machine gun position, and each part is connected by a 4.5-kilometer-long underground reinforced tunnel and river traffic trench. Each weapon is carefully arranged to maximize its effectiveness. This fortress is easy to observe in any direction. Every tunnel leading to the fortress can stop the enemy's attack. There are no exposed masonry marks or exposed buildings on the top of the fortress until the director is covered with weeds. There are four hidden turrets at the top of the fort, which are supplied with ammunition by hydraulic elevators. In order to confuse the enemy, Jun Bi also set up fake turrets everywhere in the fortress. This fortress was designed by a group of experts in peacetime. After three years of careful construction, it was completed on 1935. At that time, it was listed as one of the most important defensive positions in Europe and the strongest fortress in the world, and was figuratively compared to the "gate" in eastern Belgium and a "lock" on the defense line of the Albert Canal. The above is taken from the entry Eben Emar Fortress in the interactive encyclopedia.