Catacomb - an underground cemetery, especially one consisting of tunnels and rooms with recesses dug out for coffins and tombs
I debated whether or not I should post this video. But not posting it meant leaving out one of the most astonishing and jaw-dropping experiences of my Paris experience. There's nothing like walking through a dimly lit tunnel twenty meters below the ground to see a glimpse of those that came before us.
As you can probably guess, viewer discretion is advised.