In 2013, Hurricane Sandy pushed a wall of water into New York Harbor, turning streets into rivers and basements into lakes. A power station on the lower west side of Manhattan was one of the first buildings to flood; the circuits shorted out immediately, plunging much of the city into darkness. Fifteen blocks north, the whir and bustle inside the U.S. Postal Service’s Morgan Processing and Distribution Facility was replaced by the sound of sloshing water, as employees there worked without power under the dim glow of emergency lighting.