The old tunnel, that used to lie there under ground, a passage of Acheron-like solemnity and darkness, now all closed and filled up, and soon to be utterly forgotten, with all its reminiscences.

— Walt Whitman, writing about the Atlantic Avenue Tunnel in 1861

Bob Diamond had been guiding tours in an abandoned subway tunnel under Atlantic Avenue for almost 30 years when he was blindsided by a phone call from a New York Daily News reporter asking him how it felt to get kicked out.

Diamond was confused. His relationship with the city was getting increasingly rocky, but he had a contract for use of the tunnel.

“Look, it’s a misunderstanding,” he told the reporter. “They didn’t kick us out. Why would they?’”

But the reporter was right. The next day, December 17th, 2010, Diamond got a letter from the Department of Transportation (DOT) informing him that his contract had been revoked. The letter included a note from the New York City Fire Department (FDNY) that “strongly recommends … that the present use of the tunnel is discontinued forthwith” due to safety concerns. There was no other explanation.

The Atlantic Avenue Tunnel was sealed in 1861, shortly after Brooklyn banned steam locomotives within city limits. Legend has it that the tunnel was reopened in the 1920s when it was used for mushroom growing and bootlegging, and in the 1940s when the FBI opened it looking for Nazis. But soon after, it was lost. In the 1950s two historians attempted to find it and failed.

When Diamond rediscovered the tunnel in 1980, he was just a 20-year-old engineering student on a scholarship. The media made him a hero. He decided to restore the tunnel for the city instead of taking an engineering job. Gradually he built a career — and an identity — around the 169-year-old underpass.

Suddenly, all that was gone.