In the depths of the City of Lights’ bowels, amongst the sewer lines lies the Le Musée des Égouts de Paris (Paris Sewer Museum). The museum pays homage to the city’s elaborate sewer system, with tours dating back over 200 years. These Parisian sewers are large enough to accommodate comfortable walkways so tourists can navigate the streets subterranean-style, as the sewers have matching streets signs and addresses to the inlets for the drains above. Be warned, though: these are sewers of one of the top 25 most populated cities on the planet. So no matter how exquisite the system is, the stench can be unbearable at times.