When a hole was being dug in the backyard of this Greenlawn split-level, the children who lived there thought it was for an in-ground pool. It was actually for a nuclear bomb shelter.

The house, which is on the market for $587,000, was built in 1959 and the shelter was added during the 1962 Cuban missile crisis, says listing agent Luciano Nemes of Douglas Elliman Real Estate. The shelter is accessed by a door in the basement’s laundry room. A ramp-like crawl space leads down to the main room of the shelter, which includes a fresh-water tank reservoir, a toilet, electricity and two air-filtration systems. A hallway leads to a separate room with multiple bunk beds and storage.

advertisement | advertise on newsday

The subbasement bunker, with concrete walls and reinforced steel beams, was installed by the home’s original owner, who was an engineer, Nemes says. The shelter, he adds, also includes an emergency staircase with double-metal storm doors that lead out to the yard and emergency dig-out exits built into the wall behind cinder blocks.

“You’re meant to hit it open if the two main exits are blocked,” Nemes says of the dig-out exits. “There’s a shovel behind the bricks and you dig your way out of the shelter.”

The four-bedroom house, with two full bathrooms and two half-baths, has a formal living room that opens to the dining room. The master bedroom boasts a private bathroom and his-and-her closets. Off the den, which includes a brick fireplace flanked by built-in bookshelves, sliding glass doors lead to a sunroom.

The bomb shelter was built in 1962 during the Cuban missile crisis at the Greenlawn split-level listed for $587,000. Photo Credit: Douglas Elliman Real Estate

The wooded one-acre property, with taxes of $16,218, includes an attached two-car garage, a built-in barbecue and fire pit, and playground equipment. The concrete slab that tops the shelter has been converted into a slate patio.