One of the places I wanted to visit in Paris, was the Catacombs. The place is amazing - at first you have to stay outside queuing before you can go down 130 steps. Two kilometres of gloomy tunnels full of bones and skulls! The real Empire of Death!
When you finally see the daylight again, bags and backpacks will be checked again... no souvenirs allowed!
"Arrête! C'est ici l'empire de la mort" ("Stop! Here lies the empire of death")