Paris Sewer Museum
Yes, you read that correctly. Les Egouts de Paris (the Paris Sewer Museum) lets you go below the City of Lights to tour some of its historic sewage and water system, some of which dates back to the 1300s.
On the tour, you'll learn about the evolution of the city itself and view collectors, a main waterway, storm overflow management systems and old and new equipment.
Luckily, photography is allowed, or otherwise no one would ever believe you spent your Parisian vacation slumming it with the rats.
Tom Cooper | Elite.