The ladders are quite weird! The viaduct Garabit has ladders of helical form.

Reservoirs of the Plaine Saint-Denis (here, the smallest tank), located under the France stadium are one of the largest type of construction. It can hold up to 165.000m ³ of water. The irregular shape of the pillars is due to the construction technique by molding (digging the soil, concrete injection and clearing the land around the pillar).

Curiosity, while the soil underground is gross, it is possible to call an elevator to the surface in music! Of course, this stage is not on a secret control panel, it is not possible to go down this way (unless you have a key, perhaps).

The wind tunnel crawl of the defense.

According to various persistent rumors, the galeries network could be open to the public in the near future, and maybe offering the preservation it deserves.

Meanwhile, various underground openings are bringing the presence of taggers. The most paradoxical is that these openings are often carried out by lovers of heritage assets and they open to vandals every time.

Although there 5m ³ discovered human bones in 1959 during renovation of underground tunnels, it is clear that these underground were not intended to be catacombs, discovered the ossuary is merely an anecdotal reuse of the network.

The most likely hypothesis of the origin of fish bones, given the structure of the network, is a military use, or at minimum, shelter and storage.

They were excavated during the construction of the royal citadel Saint Sebastian, symbol of royal authority against Protestants during the reign of Charles IX in 1564. The citadel was destroyed 20 years after the reign of Henry III. It will write up an order for its destruction, to avoid ridicule.

The undergrounds beneath Fourviere were designed to avoid landslides by draining water.