If you’d been a child in the late 1800s, the Atlantic City boardwalk would have been a place of pure wonder. Racing across the wooden boards, saltwater taffy in hand, you could weave between the legs of big-city visitors and the rolling chairs, pushed by dapper attendants, in which the wealthy rode past grand hotels. Opposite Applegate’s Pier was a carousel, mesmerizing crowds with its hypnotic revolutions and the siren song of its organ, piping out popular songs.

Though originally designed as a temporary solution to keep the sand out of seaside buildings, the boardwalk—a simple raised wooden walkway—is an American institution. It has supported the feet of revelers for 150 years—an iconic place to people-watch, buy a hot dog, check out a sideshow or ride a Ferris wheel.

New Je...