And I don't mean with the subway, but through sewers, catacombs, abandoned quarries and tunnels littered with the bones of six million people, all interconnected as some kind of elaborate labyrinth only a few know how to navigate.
The stink of the sewers is subtler than you'd think, a creeping smell that follows you home. Our main route is the collector tunnel beneath Boulevard de Séastopol. It is a large, circular tunnel, lined with brick and flanked by two thick water pipes, one carrying potable water, the other non-potable. At the tunnel's dark junctions are Piranesian tangles of ducts and valves. The air is hot and close, the pipe alive with the sounds of Paris metabolising. Down the middle flows a canal of the city's secretions: a stew of shit, rainwater, garbage, dead animals, and anything else undesired on the surface. The walls are spattered with it. We pass around hand sanitiser and head down a catwalk along one side of the canal.
The pipes in Nadar's photographs of the sewers are gleaming and new. Georges-Eugène Haussmann, the city planner under Napoleon III, had recently gutted the city's boulevards and laid 400 miles of brand new sewer pipes. Engineers lavished money and attention on the city's cloaca. They tested and tinkered with the system: an animal carcass ran the length of the city in 18 days, confetti in six hours.
Today, the rigs of pipes are covered in soot, corroded and sinister-looking. It's been 33 hours, and we are all on edge. We have half an eye on the gas meters that Liz and Moe carry, waiting for the alert of dangerous vapours. Mainly, we are worried about rain. Even a short downpour on the surface could cause the collector to flood. Steve, who knows the world's sewers better than almost anyone, traces a little graph with his finger on a wall, showing the exponential rate at which water would rise during a rainstorm. Up to your shins, your knees, your waist, within minutes. There is a rig of pipes along the ceiling from which hang tattered ribbons of toilet paper, a sign of high tides past. It is hard to fight off the image of the six of us clinging to these pipes, keeping our chins above the flow.