Underground Clermont-Ferrand are dug in the tuff. The tuff is consolidated volcanic ash, easy to dig. Sometimes you may discover metamorphic rock inside the tuff. This is this kind of rock you can see on the left of the photo. Useless and too heavy, it was left in the underground.

This staircase is equipped with side rails, used to move up the artillery. Artillery was heavy guns mounted on wheels. A typical arrangement for bunker of this days.

A small bunker on the Anglet beach, french Basque coast.

The two towers of the church of Saint-Nizier were not built at the same time, for budget reasons. In addition to that, its history is chaotic. The church was built on ancient ruins and partially destroyed and rebuilt.

The Church of St. Nizier was built on very old ruins of a temple.

On the roofs of the Opera Bastille in Paris.

On a rooftops of the city hall of Montrouge with a lader, very usefull to climb from roof to roof.

At the entry of the quarry of Moulin sous Touvent, a sculpture on the wall, probably ancient.

Renault abandoned factory on the Seguin island

One of the underground cathedrals of city's Defense, so called because the vacuum is very large. Before the attacks of September 11, 2001, the underground were opened in the Heritage Days. Since then, all visits are canceled