The map runs to sixteen laminated foolscap pages, or about ten square feet, when I tile the pages together. I have been given it on the condition that I do not pass it on. It is not like any map I have ever seen, and I have seen some strange maps in my time. The plan of the above-ground city is traced carefully in pale silver-gray ink, such that, if you read only for the gray, you can discern the faint footprints of apartment blocks and embassies, parks and ornamental gardens, boulevards and streets, the churches, the railway lines and the train stations, all hovering there, intricate and immaterial.

The map’s real content—the topography it inks in black and blue and orange and red—is the invisible city, the realm out of which, over centuries, the upper city has been hewn and drawn, block by block. This invisible city follows different laws of planning to its surface counterpart. Its tunnelled streets often kink and wriggle, or run to dead ends. Some of them curl back on themselves like whips. At junctions, three or four tunnel-streets might spray out. There are slender highways running almost the length of the tiled map, from southwest to northeast. There are inexplicably broken grids of streets, or hubs where the spokes of different tunnels meet. Coming off some of the tunnels are chambers, irregular in their outlines and with dozens of small connecting rooms.

The map’s place names traverse a range of cultural registers, from the classical to the surreal to the military-industrial. The Room of Cubes. The Boutique of Psychosis. Crossroads of the Dead.

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