Mushroom area, exploited on stacks.

An ancient culture of fungus on stacks in the underground quarry of Herblay Conflans Sainte Honorine.

An ancient culture of fungus on stacks in the underground quarry of Herblay Conflans Sainte Honorine.

High on the right side, a small area with beautiful pillars.

The traces of mechanical cutting on the ceiling.

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.

It's easy to mount on top of a crane, there are ladders!

A site cutting of stone, deep in the underground quarry of Saint-Leu Esserent. The workers worked from top to bottom. Therefore, they should suspend their site on a scaffold, set into the wall.

The underground chapel of the quarry of Chauffours, carved into the wall, to honor the fallen soldiers during the First World War. There is also a wonderful fresco on the right.

A window frame a bit unusual, found on all floors of the CB31 tower.