Underground Paris: An Upside Down Guide to the Hidden City uncovers the passages, cellars and forgotten spaces beneath the streets. It leads readers through the vast catacombs holding the remains of six million Parisians, into wartime bunkers and vaulted wine cellars, and along abandoned métro stations. There are surprises too: a Taoist temple on a subterranean street, a tropical garden flourishing on a métro platform, and a reservoir the size of a cathedral. Alongside celebrated sites such as the ossuary at Denfert-Rochereau and the sewers below Pont de l’Alma are easily missed details – fragments of a medieval wall preserved in a car park, or a bank vault door shipped from Ohio and set beneath the Champs-Élysées. With clear descriptions and visiting details, this “upside down” guide reveals a city beneath the city, where history, architecture and invention come together — an essential companion for travellers who want to see Paris the other way up.