The black, sticky petroleum residue — bitumen mixed with crushed stone — that paves most of the world's roads, the cheap and repairable surface that made the automobile age physically possible, and a byproduct of oil refining so thoroughly spread across the planet that we now walk, drive, and build on it without noticing it is there.
Look down. If you are near a road, a parking lot, a driveway, a runway, or a playground, the surface beneath you is probably asphalt: a black, petroleum-derived material that coats an estimated 94 percent of paved roads in the United States, and dominates road surfaces in many other countries too. Asphalt is among the most widely applied materials on earth, yet almost nobody thinks about it. It is the ground we built the automobile age on — unglamorous, functional, and so pervasive that it has become invisible. It is also the material expression of a choice: to organize the world around the car, and to lay a black skin of petroleum product over the land to make that possible.