The stacks of a former mushroom bed in the underground quarry of Bazemont.

Photography in relief. Thank you to Argonaut for the second camera.

The underground cathedral, in the salt mine of Berchtesgaden.

We find the green color throughout most of the underground quarry of Gouvieux. Probably an anti-fungal copper base.

The underground quarry has 12 Gouvieux pasteurization chamber like this. The entire room was behaving like an oven. The heating system is on the side, out of the room.

Multiple entries into different sectors of the underground quarry of Eragny.

The construction of houses above the underground quarry requires new pillars of consolidation.

A corridor of access to different areas of the underground quarry of Eragny.

Masonry wall in the underground quarry of Eragny.

Due to its proximity to the underground quarry Brimborion Meudon, an urban legend said that one could reach the island by an underground passage. This is of course completely false.

Point of view on a large swath of the underground quarry of Saint-Leu Esserent. This type of stone in the quarry is called mass of gold.