Start the day at the Sewers of Paris (les Égouts de Paris) located in the shadow of the Eiffel Tower.  It’s an hour-long sub-surface walking tour of a small part of the 1,300 miles that make up the Paris underground sewer system.  Don’t worry about this tour being a stinker, it is really quite good and very entertaining.  It is one tour that, literally, you can enjoy rain or shine.  When the weather is wet, the sewers flow like rapids and when it’s hot and sunny, it’s cool and breezy deep inside.  Métro:  Alma-Marceau.   Museum Pass:  Yes
Website:  http://www.parismuseumpass.com/en/musees_infos_pratiques.php?musee_id=23

Next, get on the métro at Invalides for a 30-40 minute ride to the outside environs of Paris to the history-packed Basilique Saint-Denis.  It is the burial place of virtually all of the kings and queens of France since Clovis in 511.   During the French revolution, many of the buried bodies were unceremoniously dug up and placed in a mass grave on the site, but the monuments still remain.  In any case, it is the final resting place of monarchs such as Marie Antoinette and Louis XVI.   Don’t miss the mummified remains of the dauphin (prince) who would have been Louis XVII.  If you like the macabre, this is the place for you.  Make sure you get the audio guide – it will greatly enhance your visit.  Métro: Basilique de Saint-Denis.  Museum Pass:  Yes
Website: http://saint-denis.monuments-nationaux.fr/en/?fl_r=11

The next stop on this “I See Dead People” tour is the famous Père Lachaise cemetery located at the métro station of the same name.  It is the final vacation spot of luminaries such as Jim Morrison, Max Ernst, Edith Piaf, and many more.  Make sure you visit the cemetery’s website or get hold of a map in order to plan your visit.  The best place to buy the map is at the cemetery entrance nearest the métro station.  The grounds are widespread and the paths are winding and made up of cobblestones.   No admission fee is required. Website: http://www.pere-lachaise.com/perelachaise.htm

Next, a visit to the Catacombs, located near the Denfert-Rochereau métro station is as off-beat as you can get.  When the cemeteries of central Paris became overcrowded and unsanitary in the 1700’s, they carted off the remains of over six million skeletons and placed them in this underground ossuary.   Bring a flashlight and watch your head.  They will check you to make sure you don’t take any “souvenirs” upon your exit.   There is an admission charge of about 7 euros not covered by the Museum Pass.   Website: http://www.catacombes-de-paris.fr/english.htm

If it is a Sunday night, check out  the legendary Jim Haynes dinner at his private residence.  It’s within walking distance of the Catacombs or take the métro to the Alesia station.    Usually he gets an eclectic bunch of 75-100 people to show up.  Half of them are French but the other half are travelers just like you.    To get an invite, check out his website, http://www.jim-haynes.com