Descend into the eerie underbelly of Paris and you'll find yourself in the catacombs, a sprawling empire of skeletal remains that gives a whole new meaning to 'City of Lights' – perhaps more 'City of Bones' is apt. This underground ossuary, stretching over 200 miles if laid end-to-end, houses the remains of over six million Parisians. It’s like a proper underground city, if all its citizens decided to become very, very quiet all at once.

Established in the late 18th century to tackle the city’s overflowing cemeteries, the catacombs turned into a novel solution that verges on macabre genius. Walking through the dimly lit tunnels, you're literally flanked by walls of bones – not exactly the kind of company you'd expect for a stroll. It's a sobering thought that each femur, skull, and rib once belonged to someone who walked above ground, perhaps mulling over the very same existential questions we do now.

The ambiance oscillates between chilling silence and the echoes of distant footsteps, with the occasional whisper from the past or maybe just from your friend trying to spook you further. It's a haven for history buffs, gothic enthusiasts, and frankly, anyone curious about Paris’s less sung, (or should we say, less lively?) quarters.

Light-hearted tale or grim reminder of mortality? The catacombs walk that fine line with a grin that's all teeth – because, well, that's mostly what you're surrounded by. It’s a must-visit for those looking to add a dash of the macabre to their Parisian adventure, proving there’s more to this city than its romantic avenues and bistros. Just remember, it’s considered poor form to high-five the skeletons. They’ve been hanging around there for quite some time, after all.