Situated in a tunnel system under Paris’ streets, the Catacombs of Paris are underground ossuaries holding the remains of around 6 million people. With millions of fingers, tibias, femurs, and skulls decorating the walls, the catacombs are a popular tourist attraction in the French capital. It is a fascinating place to visit, but a bit scary, so do not go alone! Want to find an easy and fast way to get in? Then book “skip the line” tickets!