150 Nassau St. building
You wouldn't know it by looking up from the streets of lower Manhattan, but this is the funnest penthouse on the island. Creative Commons

The Beaux-Arts building located near the Manhattan entrance to the Brooklyn Bridge, just across the way from City Hall, is one of the last places you would expect to find a playfully contemporary living space.

But a couple living in the posh residence atop 150 Nassau St. has given the stately building’s four-story penthouse the kind of treatment those living in the building a century ago would never have imagined: They turned it into a residential fun house containing hidden lofts and glass doors, an indoor swing, a 40-foot steel column that can be rappelled for exercise, and, most impressively, a massive, spiraling four-story steel slide.

Featured in the spring edition of Bloomberg Pursuits, the home, known as the SkyHouse, was designed by New York architect David Hotson. The couple who commissioned the project remains anonymous. All we know about them is that they’re “mathematically minded” and that the residence is built around a dissertation of one of the clients regarding an “algorithm capable of discerning the structure underpinning complex sequences.”

If you like the idea of a slide inside a 19th century Manhattan skyscraper (and who doesn’t?), then you can vote for Hotson’s SkyHouse here.