Musée des égouts de Paris

The sewer museum may be out of sight, under the streets of Paris, but it's worth a visit, especially if you're familiar with Victor Hugo's Les Miserables, or if you're fascinated with the offbeat. The city's current sewer network was begun in 1850, although some rudimentary pipes were laid earlier, under order of Napoleon I. The visit, dotted with explanatory panels and dredging equipment, takes you around a maze of tunnels and sewer pipes. You likely won't want to make it a long one, as the smell can be off-putting. The entrance is in the riverside gardens the Quai d'Orsay and the Seine. Closed 2 weeks in Jan. METRO: Alma-Marceau (and cross bridge) or RER Pont de l'Alma