Now you can go more than 20 meters underground and check them out for yourself. They are creepy, HUGE, and what surprised me the most: wet! It was kind of disgusting and I didn't want to think about where the occasional water drip was coming from considering that the tunnels are located underneath both the metro and sewer systems.
As you can see, essentially the Catacombs are huge tunnels with stacks of human bones on either side. Most of them are arranged in semi-artistic patterns. It's quite eery as you can imagine.
There are all kinds of myths about people getting lost in the Catacombs (before they were a tourist attraction). Also, there is a black line of paint along the ceiling that was originally there to help guide people out if they got lost.
