A PENTHOUSE at the Gale International-built 21W20 has just closed at $17 million. Stephen McArdle of Halstead Property Development Marketing (HDPM) and Rachel Glazer of Brown Harris Stevens co-listed the 4,210 s/f home. According to McArdle, “The buyers saw this as a unique opportunity to live in a perfectly-proportioned home with an unrivaled combination of indoor/outdoor living space.The two-bedroom, 4-bath home with a studio, 1,740 s/f terrace and rooftop solarium achieved the third highest price ever paid for an apartment in Flatiron. “The intimate nature of this exclusive development by Gale International, the intelligence of the interior design by David Mann and 21W20’s location in the heart the dynamic Flatiron with its great restaurants, retail and parks, made for one very happy owner.” The penthouse has a roof deck with an outdoor shower, full kitchen, custom-designed gas fireplace and a six-person hot tub. The living room has folding floor-to-ceiling glass doors that open up to the 75-foot wide terrace.