The Catacombs of Paris is simply a must-see during your visit. Here the remains of over 6 millions people are stacked to form long stretches of tunnels. A few hundred years ago the city was dealing with multiple cave-ins at cemeteries throughout the city and simply not enough room to bury the dead. There's a really good article here about the churches struggle for trying to keep the cemeteries going.
I found my favorite coffee shop in Paris walking to the Catacombs and stumbled upon many cute streets, stores, shops, and cafes along the way. This was a wonderful day of exploring and a really unique memory to have. Also, I apologize for the grainy pictures, but it was really dark down there and no flashes were allowed!
Tourist Advice: Arrive as early as possible to the entrance (Place Denfert-Rochereau, 75014 Paris). There is a metro stop right across the street, but we walked from the 2nd Arr. There will likely be a queue already, walk to the doorway and get a time ticket. This is not your ticket to enter, but the time slot in which you are to come back and visit. The reasoning is because there is a limit as to how many visitors can come per hour (200), because of the historical significance of the site and in order to maintain it's integrity. For instance, we arrived around 10AM and mistakenly stood in the line for 40 minutes until we noticed other people with color-coded time tickets. So we walked to the doorway, got a time ticket and had to wait until 5:30PM to take the tour. This was only a minor inconvenience because we spent the afternoon visiting the Luxembourg Gardens and getting lunch in Saint-Germain des Près.
More from my trip to Paris soon...