The secrets of the sanctuary have been locked away for 70 years in order to preserve its wildlife.
"There's a subway right underneath," New York City Parks Commissioner Adrian Benepe said.. "There's millions of people coming through. You can hear and see the city all around you, and yet you can also hear the blue jays calling the trees above."
The trees, the living and the dead, seem like old friends now to Joel Meyerowitz.
"By being present in the moment, I make a discovery," he said.
The quest began years before he became a famous photographer, long before his work was shown in galleries and museums all over the world.
"Growing up in the Bronx, even though I lived in a tenement, right across the street from me was a tributary to the Bronx River," he said. "So there was a wilderness there."
As a grown up, Meyerowitz got the chance to wander at will in all five boroughs, taking photographs for the parks department and collecting his work in a new book from Aperture called "Legacy."
Some of the best images came from within the sanctuary.
"There were these balloons that must've fallen from a building nearby, and they were just incredibly colorful," he said. "The only man-made thing in the whole space."
The space may be closed to the public, but there's no shortage of other places to have much the same experience.
"That retreat is the same retreat that people can have in all the parks in New York City if they just cared to walk off the bike paths and the playgrounds and go into some un-managed area and commune with nature," Benepe said.
Tours of the Hallet Sanctuary are offered from time to time.
For more information, visit NYCGovParks.org.
WEB PRODUCED BY: Bill King