The Secret Spot Hidden Below New York

A subterranean mystery lingering since the 1964 World’s Fair has baffled history buffs from Flushing to Florida.

Photo by Bruce Davidson, © Bruce Davidson/Magnum Photos, Inc.

A mid-afternoon rainfall has saturated the dirt just enough that Dr. Lori Walters easily unearths some with the tip of her black loafer. A few yards away, groups of Latino men in bright t-shirts and blue jeans are playing a casual game of volleyball, bumping but never spiking, on a lazy Sunday in Flushing Meadows-Corona Park, the largest park in Queens.

Dr. Walters is tired. She has been on her feet for much of the past two days, running an exhibit at a science fair teeming with children and parents. Her fingers brush back strands of brown hair that a gentle wind has blown out of place, and she tucks her hands into the large pockets of a maroon jacket. Her slender body is weary, her voice cracking, and she still has a long trek home to Florida, where she is a history professor.

A wayward volleyball—actually an old soccer ball, which serves the same purpose—hits the hard ground with a thud. Greenery envelops most of Flushing Me…