The Catacombs of Paris are hundreds of miles long. However, only around one mile of this area is open for public exploration. The rest is deemed to be unsafe, and hence, is illegal to visit. Once inside the ossuary, one can see impressive structures of bones, which are neatly grouped in stacks or other creative patterns according to the cemeteries that they came from. In some areas, people can also see creepy sculptures created by a veteran of Louis XVs army, before the bodies were moved in. It is a really creepy/cool experience, depending on the visitor's views. Several secret entrances to the tunnels are scattered across the city. Many manholes also have access points into the catacombs. However, visiting these areas without official permission is illegal since November 2, 1955. There is a special police force assigned to prevent trespassing into the tunnels, and if caught, a person can face large fines. Despite this, there is a pretty active subculture of 'cataphiles' (illicit explorers) who know a lot about the tunnel system, often holding invite-only parties and concerts, which one can find only if they know the way around. It is rumored that, one can find entire fully-furnished squatter villages, artifacts from a number of wars, and much more there. In fact, the tunnel police recently found a fully functional movie theater in this area. With the number of skeletal remains in the catacombs, it is one of the top contenders for being the most haunted place in the city. If one surfs the net looking for videos of people catching images of spirits on tape, the results can be quite convincing. On the other hand, many paranormal investigators disagree about such hauntings, saying that, since no one has died within the catacombs, the chances of a haunting here are extremely slim.

• The location of the Catacombs of Paris is 1 Avenue du Colonel Henri Rol-Tanguy, 75014 Paris, France. To get here, use the Paris Metro stop Denfert-Rochereau or the Paris RER B stop Denfert-Rochereau; Paris bus lines 38 & 68 also stop near the catacomb entrance.
• If you are driving, you can park at the Saint Jacques Boulevard. The catacombs are open from Tuesday to Sunday, from 10 am - 5pm. The admission fee is approximately USD 11 for adults.
• Be sure to wear warm clothes when you visit, as the temperatures in the tunnels are nearly always cold and chilly, at around 60°F/15°C.
• It is ideal to visit the catacombs early in the day, on weekdays, as this is the time when the crowds are the least. The experience is enhanced when there are fewer people around, and best if you are alone.
• Although there are no guards in the catacombs, touching the bones is prohibited. Most importantly, don't try to steal anything (not only is it illegal, it is also totally gross). The guards at the exits check each visitor meticulously, and occasionally, one can see a few bones on a nearby table, which have been removed from the bags of tourists.
• The floor in some areas is dusty/wet. Therefore, it is a good idea to avoid wearing your best pair of shoes to this place. Also, some of the ceilings in the passageways are quite low. So, if you are a tall person, watch your head.
• When you have finished your tour, you will find that you have come out into a completely different neighborhood, which can be a little disorienting. The nearest metro station from the exit is the Mouton Duvernet. To reach there, turn right from the catacomb exits, walk a couple of blocks till you reach a street named Avenue du General Leclerc, turn right again, and keep walking till you see the entrance to the station.

So, the next time you are in Paris, make sure to check out this place. You won't regret it. Only make sure that there are no skeletons following you when you leave, and you'll be fine.