A friend of mine once had a devastating fire in his apartment. It wasn’t his fault. The wires behind his walls were bad. “You always forget,” he said, “that behind every smooth wall hung with pictures is a bunch of energy that’s always on.”

Same goes for city streets. A labyrinth of gas, water, electricity, transformers and cables lurks hidden underground. The grid’s power is immense and unforgiving. It refuses to be ignored. A manhole cover blows, a giant sinkhole opens, your gym’s glass windows blow out, or a pipe in the middle of traffic simply needs to let off steam. Then we remember. There’s an entire world below our feet, and, guess what? It’s alive.