Paris, like a lot of cities, has been running out of burial space for centuries. In 1785, the authorities of the city had a creative solution — transfer all the remains from the cemeteries into the abandoned quarries under the city. Over the next hundred or so years, a total of six million bodies were moved and reinterred, stacked up against any available surface.

It’s been open to visitors on and off almost since it was created. One of the directors in the early 1800s had the bones arranged into the patterns you see today, as well as installing the forboding signs (including the famous “Arrête! C’est ici l’empire de la Mort” at the start). But it’s really about wandering through the corridors amongst the hundreds of thousands of bones there. I’m a fan of the memento mori, the reminder of one’s mortality. Here, you have your choice of one.