Another fact not mentioned in this article is the WWII historical locations found in the unofficial Catacombs. Back when I lived in Paris, I was lucky enough to know someone who had access to one of the Cataphiles' maps (yearly-updated with notes on entrances and potential police patrols, with closest exits and dangerous passages).<p>We visited an old school basement, which was used as a bunker for members of the Resistance. The school itself was razed and rebuilt over at some point, but the Catacombs still hold traces of this period. Being there felt very...intimate. Nothing like you'd see in a museum or a documentary, we were in the same place as those back then.