Who says you have to grow up? A playful four-story penthouse in lower Manhattan wants to help you unleash your inner child with whimsical features that are sure to spark nostalgia.

Named Sky House, the four-bedroom residence is the crown jewel of a 23-story landmarked building in New York City’s Financial District. The Beaux Arts skyscraper is the former headquarters of the American Tract Society, a religious printing house that exited the property in 1914. It was transformed into a 125-unit luxury condo by 2002, the pinnacle of which is a quadplex with an 80-foot stainless-steel slide, a rock wall, and a rope swing.

Tech executives Craig and Kirsten Nevill-Manning bought the property for roughly $6.45 million in 2007, The Wall Street Journal reports. The couple tapped architect David Hotson and interior designer Ghislane Viñas to realize their vision of a highly customized pad that blurs the lines between architecture, art, and play. It took over five years to complete the home, underscoring the complex nature of the design and build. The result is a highly distinctive penthouse that doubles as a fun house.

With extensive glass and open spaces throughout, the apartment has a light and airy feel. The entrance gallery gradually opens to nearly 6,400 square feet of interiors on the main level, with the mirrored slide serving as the sculptural centerpiece. Further in lies a 12-seater dining room and a living room with a soaring 43-foot-tall ceiling and massive arched windows that spotlight Big Apple landmarks like the Manhattan Municipal Building and One World Trade Center. Nearby, there is a riveted steel column fitted with grips for rock climbing and a rope swing for extra thrills.

A few steps away, the open-concept kitchen is decked out with a hidden pantry, plus Gaggenau and Miele appliances. Dual sets of double doors lead to a 1,200-square-foot terrace with alfresco dining and lounge spaces. Back inside, a corner primary suite offers yet more vistas and a minimalist bathroom with heated floors and dual vanities.

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Heading upstairs, the mezzanine is equipped with a catwalk that overlooks the remarkable architecture below and a study in which you can handle important business. The third floor is home to three guest bedrooms, a floating lounge area, and a wraparound terrace, while the fourth floor sports a gym and the entrance to the slide. To top it off, the sky-high digs sit right by buzzy FiDi spots like South Street Seaport.

Sky House is now available for $20 million, with Nick Gavin, Ugo Russino, and Allie Fraza of Compass holding the listing.

Click here to view more images of the Manhattan residence.