A Kensington resident says an important piece of Brooklyn's history is buried underground, and he is demanding the city make the discovery public.

Bob Diamond rediscovered the Atlantic Avenue tunnel in 1981, which according to the Guinness Book of World Records is the world's oldest subway tunnel. It was used in the mid-1800s by the Long Island Rail Road. The city allowed Diamond to give tours of the tunnel until his access was cut off in 2010.

Diamond says he was no longer allowed in the tunnel because he partnered with National Geographic to scan the area with high-tech equipment. He says the results found an old steam locomotive.

"Besides having something that's extremely historic and cultural, it's going to bring hard cash into the neighborhood when tourists come from around the world to see it," said Diamond.

He hopes the city will work with him to open up the tunnels again and unveil the locomotive to the public.

A spokesperson from the city's Department of Transportation told News 12 that the city revoked its access to the tunnel for safety reasons in December 2010. They added that the matter is still in litigation and they cannot provide any further comment.