Farther below this the walls are usually brick or stone, or concrete. Some are made of steel or aluminum. The metal ones are sometimes corrugated and are usually galvanized or painted. Murals and tapestries are common. The artists who create such things are revered. Windows that were once high above lawns are now at knee level and look out over courtyards of metal benches standing on asphalt that was once a roadway. The stripes are still visible. One can never escape the hum of the lights or the dull roar of the thousands of power plants buried deep under what was once the surface of the earth. People live in shifts because no sunlight penetrates this far. Most stores are always open but smaller ones close when the owners sleep. But the machines always have to be minded, or else the tangle of exposed steam pipes might grow cold. Storefronts are stacked upon each other. One can often see them stretching upwards or downwards through gaps in the platforms. They are of all types, and sometimes they consist of an upper level of a multi-story building that has been given an exterior door and a facade. ascend descend