Megapolisomancy is the concept of designing a city with a larger purpose behind everything in order to harness the magical power of the millions who inhabit it. It is partially or directly related to concepts put out by Lovecraftian magic, Urban or city magick, and chaos magick, as well as a healthy dose of conspiracy theories and what not.
The Windy City [Chicago] is the birthplace of urban horror. Riding on the L with a faceless mass of drones being herded back to their soul-crushing jobs, Fritz Leiber looked out across the sooty rooftops and envisioned the kinds of ghosts that the metropolis demanded. In his classic novel Our Lady of Darkness, Leiber invented the arcane science of megapolisomancy, the magic of cities. Or so the story goes.
Is it possible that Leiber didn't create a fictional concept, but instead revealed a hidden truth? Were the street plans for the great American cities laid out like circuit boards to channel psychic energies, with steel-girdled skyscrapers designed as capacitors to store up these forces until they were needed for some cosmic ritual?