Something I did not know, despite being unhealthily obsessed with Paris to some degree: the city sits atop an incredible maze of caves, tunnels and catacombs.
From National Geographic:
Paris has a deeper and stranger connection to its underground than almost any city, and that underground is one of the richest. The arteries and intestines of Paris, the hundreds of miles of tunnels that make up some of the oldest and densest subway and sewer networks in the world, are just the start of it. Under Paris there are spaces of all kinds: canals and reservoirs, crypts and bank vaults, wine cellars transformed into nightclubs and galleries. Most surprising of all are the carrières—the old limestone quarries that fan out in a deep and intricate web under many neighborhoods, mostly in the southern part of the metropolis.
Into the 19th century those caverns and tunnels were mined for building stone. After that farmers raised mushrooms in them, at one point producing hundreds of tons a year. During World War II, French Resistance fighters—the underground—hid in some quarries; the Germans built bunkers in others. Today the tunnels are roamed by a different clandestine group, a loose and leaderless community whose members sometimes spend days and nights below the city. They’re called cataphiles, people who love the Paris underground.
Now enjoy this video from La Blogothèque that features Sigur Rós performing “Hrafntinna” in a cave under Paris. It’s just lovely.