The Catacombs is the final resting place of more than 6 million bodies representing about 30 generations of Parisians.

Paris, its known for is Renaissance architecture, its Art Deco-influenced fashion and its heavily artistic culture, but beneath the largely residential 14th arrondissement, lies the most eye-popping, chill-inducing and slightly claustrophobic attraction that has given prominence to the cosmopolitan capital of France as one of the greatest funerary sites ? the renowned underground ossuary known as the Catacombs of Paris.

Composed of a network of labyrinthine tunnels first excavated during the Roman period, the Catacombs of Paris are now the home of over 6 million burials, removed from overcrowded cemeteries and charnel houses all over Paris during the late eighteenth and nineteenth centuries.  Bones that had been exhumed from the notorious Cimetiere des Innocents and transferred to the underground grotto. While today flocks of tourists travel from far and wide to glimpse the site of Paris' Catacombs with hushed curiosity, it wasn't always a tourist attraction, nor was it intended to be.

As far back as the Roman times, Paris had long buried its dead on the outskirts of the city, but as Christianity continued to influence beliefs, habits soon changed to incorporate the practice of burying its faithful in the consecrated ground under and around churches.

With many of Paris's parish cemeteries located within the city limits, dense urban growth hindered the expansion of cities, forcing cemeteries to become overcrowded. To remedy the situation, the opening of a mass burial ground for those who were not wealthy enough to pay for a church burial was created in the early twelfth century.

Known as the oldest and largest cemetery in Paris, Cimetiere des Saints-Innocents (The Saints Innocents Cemetery) first opened offering individual sepulchres, however, with a need to reserve space a pit was created for mass grave burials in which upwards to 1,500 bodies could be placed before being filled to allow a new pit to be opened.

By the fourteenth and fifteenth century, Cimetiere des Innocents soon became overcrowded with mass graves, prompting citizens to construct arched structures known as charnel houses (charniers) along the cemetery walls, where the bones of the deceased could be deposited. It was between 1423-1424 that the earliest depictions of Danse Macabre had been painted on the cemetery walls.

Soon, in the eighteenth century, during the reign of Louis XV, the sanitary conditions around Saints Innocents had grown unbearable. Recorded accounts made by inspectors detailed the difficulties in conducting business in the area due to the overuse and incomplete decompositions of bodies. With residues resulting from the decay of organic matter (chemically accelerated by the use of lime) entering directly into the earth,  the city's principal source of water – well water was quickly contaminated.

Because Saints Innocents was Paris' most sought-after cemetery and the largest source of revenue for the parish and church, the clergy continued conducting burials. To appease the citizens two edicts by Louis XVI requested parish cemeteries be moved out of the city. However, the church resisted the edicts as burial fees had proven quite profitable. Instead, to reduce the number of burials, the price was increased.

By the end of the eighteenth century, the city's cemeteries had begun to overflow with the rotting remains of human cadavers in various states of decomposition. With the piles of bodies increasing and disease spreading rapidly, a prolonged rainstorm in the spring of 1780 made conditions more untenable. No longer could the church parish ignore the edicts imposed by Louis XVI, as they were prohibited from burying any more corpses in Les Innocents and further condemning all existing cemeteries within city limits in September of 1780.

The vast Catacombs in Paris are located in 186 miles of underground tunnels.

While it would be roughly 30 years before Paris saw new cemeteries built near the city, the government had been searching for and consolidating long abandoned stone quarries in and around the capital since 1777. It was during the time of Les Innoncents' closing that Inspection generale des Carrieres (Inspector General of Quarries) and Police Lieutenant General Alexandre Lenoir (who had been overseeing the renovations of the quarries) proposed the idea of using the empty underground tunnels on the outskirts of the capital to house the remains as an underground boneyard.

However, with the council having decided to convert the Roman-era limestone quarries into a mass tomb, it was Lenoir's successor, Thiroux de Crosne, who chose a location south of Paris's porte d'Enfer city gate. Since the eve of the Catacombs' consecration ceremony on April 7th, 1786, the transfer of exhumed bodies began under the shadow of night and with deep reverence. Behind the procession of chanting priests, a parade of black-covered, bone-laden, horse-drawn carriages made round trips from cemetery to purchased land, where the bones were deposited, and further distributed throughout the underground caverns by workers below for the following two years.

For the first year, the Catacombs had become primarily a bone repository, but it was French politician, man-of-science and mining engineer, Louis-Etienne Hericart de Thury, who oversaw the renovations that would transform the 186 miles of underground tunnels into visitable ghoulish underground sepulture. Using cemetery decorations and tombstones to compliment the walls, he directed the arrangement of skulls and femurs into romantically-macabre artistic patterns, displaying the beauty in bones.

The Catacombs itself has long captured the awe of curious visitors eager to experience the subterranean journey which begins down a seemingly endless flight of narrow stone stairs. It's only after the descent that tourists will proceed through a long, dimly lit, dank and oppressively cramped passageway leading to an entrance with a greeting carved in the lintel which reads, “Arrete! C'est ici l'empire de la mort.” (Stop! This is the kingdom of the dead). It's only after crossing the threshold that visitors find themselves wandering past a series of large recesses in the stone walls, each fronted by a retaining wall of skulls, tibias and femurs, all of which have been artfully arranged. Further inspection sees an enormous pile of indiscriminately commingled bones, some neatly stacked around various memorial plaques.

The walls of the Catacombs have been marred with graffiti dating as far back as the 1800s, and for over a century have been used to house the bodies of the dead from the riots in Place de Greve, the Hotel de Brienne and Rue Meslee, and further have been used by communards, Parisian members of the French Resistance as well as German soldiers.

While the Catacombs have given Paris the space to bury its dead, the tunnels themselves have presented a disadvantage in the architectural structures of many of Paris' buildings. Because large foundations cannot be built over the quarries for fear of causing a collapse, not many buildings in Paris are built at exuberant heights.