A swift post to flag up this epic article on underground Paris, The Lizard, the Catacombs, and the Clock: The Story of Paris’s Most Secret Underground Society’, an article by Sean Michaels at Brick Magazine.
However, the people responsible for the cinema under the Trocadéro, a place they dubbed the Arènes de Chaillot, are not quite any of these things. “We are the counterpoint to an era where everything is slow and complicated,” they explain. This group also balances the aspect of today that is instant and shameless, hysterically tweeting. They are patient, serious, and they keep their secrets.
There are extensive maps at this Catacombes of Paris page, which leads to this epic zoomable Catacomb map (2010 International edition, section reproduced above), photographs here at Lightningfield (last updated nearly three years ago…) and more at this flickr set.