1 - The largest crypt in Europe is located in Boulogne-sur-Mer
The basilica of Boulogne-sur-Mer hides one of the most unusual and surprising places in the region! Beneath our feet lies the largest crypt in Europe. An absolutely sublime architectural gem spread over 4000m2. Corridors, secret passages, numerous rooms, and above all colorful frescoes and murals!
2 - The Grand Place of Arras hides a city beneath the city
Take a few steps down and take a leap of 1000 years into history! The city of Arras hides an underground city 12m deep. You can visit its boves just below the Grand Place. "In just a few steps of stairs, travel back over a thousand years of Arras history, from the Middle Ages to the shelters of World War II. These underground galleries dug into the chalk plunge us into the depths of a timeless city. Decipher the symbols carved in stone and let yourself be enveloped in a maze of shadows and light." (learn more here)
3 - The Underground City in Naours
Streets, intersections, squares, and even... houses! The underground city of Naours is a true medieval village beneath our feet. These types of places are called "muches." They are underground chambers that can serve as a refuge in times of war, pillaging, or invasion. The muches of Naours have survived through the centuries, with 300 of them hidden right there without us even realizing. Set up like a real living space, there are even chapels, common areas, and spaces for livestock. A true city organized like a separate entity!
4 - The Mimoyecques Fortress: an ultra-secret World War II bunker
Incredible but true! This absolutely gigantic underground bunker is a huge secret from World War II. So secret that it was given a code name so it wouldn't be found: Wiese Bauwerk 711. "The visit to this gigantic underground bunker that plunges deep into the hill is impressive. There is a particular atmosphere throughout the hundreds of meters of galleries open to the public. One can grasp the extent of military armament that pushed the technological boundaries of the time: the initial project included a system of galleries, an underground railway line, and 5 launch shafts each housing 5 super cannon V3. A 127-meter long cannon capable of firing 3 shots per minute with a range of 165 km." (learn more) Hitler planned to make it the largest cannon in the world. In secret from the French, Churchill orders its destruction.from the fortress of Mimoyecques in May 45.
5 - The Underground Citadel of Cambrai
At the heart of the underground galleries of the Citadel of Charles Quint is a real hidden network. A maze of secret corridors to protect the city. A defense system that was later abandoned in the 19th century. Today, you can visit this defensive system under our feet with the Tourist Office of Cambrai. Only during guided tours! 🗝️🗺️☀️
