In the spring of 1780, Paris was wet and miserable. The rain would not stop. Mud plastered everything and water soaked the earth so thoroughly, that on May 30th, a cellar wall bordering the huge Les Innocents cemetery collapsed. Rotting bodies and stinking mud poured into the building, and even after the cellar was emptied and repaired, the masonry sweated a stinking ooze that reeked of decomposing flesh.

The Les Innocents cemetery had been a problem for centuries. It was the burying place of the poor, its earth used for mass burials. A body would be dropped into a massive pit and covered for a time (a time which grew shorter and shorter as the cemetery became fuller and fuller), to be dug up later and the bones removed to cubbies, known as charniers, that lined the cemetery walls. While the bones were removed, the fleshy, fatty remains stayed in the soil, concentrating the noxious and infectious emissions of millions of dead Parisians.

It was a public health disaster just waiting to explode, but the cure was readily at-hand. On the outskirts of Paris lay a network of tunnels created by the mining of limestone. Veins of quality building stone had been pursued far underground to satisfy the city's rapid growth, and so much had been excavated in some areas that the above-ground actually become unstable. Entire buildings collapsed. It was such a safety hazard that in 1777, a special government agency, the Quarry Inspection Department, had been formed to map and regulate the quarrying efforts. It was only a matter of time before an intrepid thinker connected two problems into one glorious solution: close the above-ground cemeteries, especially Les Innocents, and remove the remains to the underground tunnels.

At first, the remains were simply dumped from tipcarts into the underground caverns. This was performed at night to the accompaniment of the reading of last rites. The six million bodies of Les Innocents went first, but by 1792, all the graveyards of France were being emptied and transferred to the great ossuary, tumbling the remained into deep pits and tunnels. It wasn't until 1808 when Hericart de Thury, an official with a certain appreciation for the underground, began a reorganizing campaign. His an intent was to open the catacombs to viewers. The remains were carefully organized, the skulls and leg bones stacked into strange walls that still greet visitors today. De Thury also added the macabre, yet humorous, plaques that wink slyly at viewers mortality. "Arrete!" one says. "C'est ici l'empire de la mort." ("Stop! This is the empire of Death.")

The empire of Death, once just outside of town, has been built over by Paris's busy streets. Today, the 300+ kilometers of tunnels, many full of the millions of Paris's pre-1814 dead. That's when the ossuary was closed to new inhabitants--but not to new visitors. The catacombs have been explored by a range of historical figures: the Nazis carefully mapped the underground network while the French Resistance used the tunnels to secretly do the work of retaking their city. French aristocracy partied in the catacombs, and Napoleon III took his son down there to explore.

If you're interested in visiting the catacombs, you're out of luck. They're overseen by the Paris Museum, and according to the webpage, are currently closed to visitors. Visiting on your own is extremely illegal. And dangerous. Your best bet for a taste of Death's empire is the truly terrible movie "Catacombs." It was filmed in sets carefully replicated from the real Paris catacombs and is mercilessly creepy.

For more information, check out:
Steves, Rick (et al). Rick Steve's Paris 2009, Avalon Travel, 2008.
The Museum of Paris Catacombs: http://www.catacombes-de-paris.fr/english.htm
The Catacombs of Paris cartography page: http://www.catacombs.explographies.com/
Paris Promenades: Walk III, Les Innocents Cemetery: http://www.paris-promenades.com/en/site_text/III.htm