[...] it was one of the best places to be as Paris sizzled. Tucked deep underground, the museum maintains an even temperature, and the ambiance, while a little smelly in parts, is not overwhelming. Walking past a canal, its dark surface prettily reflecting the glow of tunnel lights, I saw tiny bubbles popping on the surface, creating an effervescent sparkle. Exhibits trace the history of Parisian sewage from the Middle Ages, when streets had drains for wastewater in the middle, to the current incarnation, which got a major overhaul in the mid-19th century under the supervision of city planner extraordinaire Baron Haussmann and engineer Eugene Belgrand. The current system is unusual in that it also includes conduits for drinking water, handles rain runoff and houses telecommunications cables. Displays of equipment, some antique, some current, show the tools used to keep the tunnels clear - workers remove about 15,000 cubic meters of solid waste per year. Like all good museum tours, this one ends at the gift shop where you can buy mementoes of your visit including stuffed (toy) rats.