Lurking underneath Paris’ bustling streets is a complex maze of macabre tunnels and tributaries known as “Les Catacombes.”

The story of its morbid history began back in the mid 1780s at a time when Paris’ largest cemeteries had become unbearably overcrowded. It was deemed that the mortal remains of Paris’ inhabitants would have to be transferred to the disused underground stone quarries to relieve the appalling sanitary conditions that had arisen in the Parisian cemeteries because of the poorly managed, rapidly decomposing human remains.

The first of around six million skulls and bones were transported to the ossuary in 1786 before the contents of a further sixteen cemeteries from around the city were subsequently re-interred.

Inevitably the dank nooks and crannies went on to become something of a tourist attraction during the 19th Century. Nowadays, you may even have to wait up to 90 minutes to take the tour that leads you through the skull-laden corridors that trace a cramped 2km path beneath the city. Les Catacombes are perhaps best summed up by the ominous proverb engraved onto the entrance to the ossuary itself: Stop! This is the empire of death. Quite.