For many, Brooklyn’s underground mysteries start and end with the question of when the F train will arrive. But there are more to ponder: Brooklyn is home to a surprising number of nearly forgotten or recently rediscovered abandoned tunnels.

Some of Brooklyn’s underground tunnels, like those connecting the Jehovah’s Witnesses’ portfolio of real estate, are relatively well known to Brooklynites, while others are more obscure.

Below, three tunnels even native New Yorkers probably don’t know much about.

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The Abandoned Staten Island-Brooklyn Tunnel

What a game-changer it would be if Staten Island was connected to the subway system! It almost happened in the early 20th century — an attempt was made to create what would have been the first-ever rapid-transit connection between Staten Island and the mainland, namely Brooklyn’s Bay Ridge neighborhood.

“They Called the 1923 Narrows Tunnel ‘Hope and a Hole in the Ground’,” reads the title of a 1964 article in the former Bay Ridge–based newspaper Home Reporter and Sunset News.

Originally the intent was to create a passage for freight and passenger trains, traversing the Narrows (the tidal straight that divides the two boroughs) from St. George in Staten Island to 5th Avenue in Bay Ridge.

Construction was initiated on both sides, with tunneling shafts sunk beneath both Shore Road and the Saint George Terminal.

Formally called the Brooklyn-Richmond Freight and Passenger Tunnel, the City of New York was mandated to create it in a bill passed by the state legislature in 1921, the Home Reporter article said.

A debate ensued as to whether or not the tunnel should carry subway trains. But then, due to a lack of funding and political rivalries, the project’s construction was halted and abandoned in 1925, leaving 150 feet of unfinished tunnel beneath the Narrows, according to Atlas Obscura.

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Atlantic Avenue tunnels

What might well be the world’s oldest subway tunnel was built in seven months in 1844 underneath Atlantic Avenue. Known as the Atlantic Avenue Tunnel, the subterranean portal runs beneath Brooklyn Heights and Cobble Hill, according to the Brooklyn Historic Railway Association.

Long abandoned, it was rediscovered by transit enthusiast Bob Diamond in 1980, who proceeded to lead popular tours through the space for three decades until the Department of Transportation in 2010 told him to stop on the basis of safety concerns.

Diamond proceeded to sue the city for $100 million over the matter. To this day, he believes, there is a 19th-century steam engine located somewhere in an inaccessible portion of the tunnel.

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Colonial Tunnels in Gravesend

Tunnels below Gravesend’s Lady Moody House connected to a now-demolished house on the site of the Gravesend cemetery and protected the nascent Gravesend community during the Indian wars of 1645 to 1646, according to Gravesend Historical Society President Eric Ierardi. Also known as the Van Sicklen House, the largely 18th century structure at 27 Gravesend Neck Road was landmarked earlier this month.

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