Off-market? Maybe. Unreportable? Absolutely not. This 25-foot-wide Upper East Side townhouse is pure architectural drama—with colonial bones and a century of very cool secrets.

Nestled atop the historic Sohmer Piano Building in Manhattan’s Flatiron District, the sale of this opulent property will directly support the restoration of Mozambique’s Gorongosa National Park.

Set high on the 26th floor of the iconic Robert A.M. building on 15 Central Park West, this chic Manhattan residence reflects the designer’s simplicity and wabi-sabi aesthetics.