What was once a super-secret underground command bunker is now... an exciting museum in Heuvelland

Between 1952 and 1956, in the midst of the Cold War, top-secret excavation and construction work took place under the southern flank of Kemmelberg in today's West Flanders municipality of Heuvelland. Here Benelux, France and Britain built a coordination post deep underground for a Western European air defence system. It is now a museum of military history. 

At 64 Lettingstraat in Heuvelland, you will find an unremarkable rectangular house in red brick with an equally plain gabled roof. The surroundings exude rural calm and tranquillity. But appearances can be deceiving. The building camouflages a Cold War relic, a defensive position that would warn against a possible threat or attack from the Eastern Bloc. The construction site was completely hidden from view, so the few local residents were none the wiser. The construction workers had no idea what they were actually building either and were regularly replaced. Even at Belgian Defence headquarters, hardly anyone knew about the military project. What took place here remained shrouded in mystery for decades. It was the Belgian military's best kept secret until after the fall of the Berlin Wall in 1989. Only the chimney pipes of the air ventilation could have put dedicated sleuths on the trail of an underground riddle. 

The camouflaged house is built over a floor hatch, which provides access via stairs to the 15 m lower central operations quarter on levels -1 and -2. This was the nerve centre of the command bunker, with a large map room. From the meeting rooms and their surrounding office on Level -1, the staff of the land, sea and air forces had a clear view of this 'beating heart' of the structure through a glass window. The actual bunker measures 30 x 30 m, has 3 m thick walls and has a floating concrete roof which is 1.15 to 2.90 m thick. The layer of soil between the roof and the bunker was designed to cushion the shock in the event of bombing and the copper sheathing around the outer walls were to protect against electromagnetic radiation. There were also technical installations such as two diesel generators for power supply, heating burners, air ventilation, a communication system, telephone exchange, telex equipment, radio service and military postal service. 

But it was never used for air defence 

By the time the bunker was completed in 1956, NATO had installed its own defence system. In the end, the Kemmelberg bunker also proved not to be NBC safe, i.e. not resistant to the impact of nuclear, biological or chemical weapons. From 1963 to 1995, it served as a secret command centre in case of war or conflict and for large-scale training purposes. In 2009, the Royal Museum of the Armed Forces and Military History converted the command bunker into the engaging museum for young and old that it is today.