Catacombs
In damp and dreary underground tunnels, dug in former Parisian quarries lay the remains of six million Parisians. Skulls, tibias, femurs are compactly and decoratively stacked. This ossuary was created in the end of 18th century when bones from the overflowing Cemetery of the Innocents located in the Halles district were removed and relocated in these old quarries. The removal of the bones took place every night for two years (1786-1788) in a long and lugubrious procession across Paris. Bones of famous historical figures such as Madame de Pompadour, Mirabeau, Rabelais are among the remains. (Metro: Denfert Rochereau)
Pere Lachaise Cemetery
This is the largest cemetery within central Paris and the most famous. Strolling along the neat winding paths and leafy alleys you can visit the graves and mausoleums of many historical figures including Heloise and Abelard, Moliere, Victor Hugo, Proust, Chopin, Oscar Wild and Jim Morrison. (Metro: Pere Lachaise)
Sewers of Paris-
In Victor Hugo's novel Les Miserables, Jean Valjean tries to escape through the labyrinth of the sewers of Paris. The system dates back to the late 1300's and has been over the centuries enlarged to cover a network of over 1300 miles of sewer tunnels. A visit of the museum of the Sewers of Paris will let you explore the galleries with large displays explaining the history of the sewers, the engineering and how Paris handles waste water from elimination to purification and drinking water. It is interesting to know that each sewer street mirrors the street above. (Metro : Pont de l'Alma)