Geoff Manaugh of BLDGBLOG took a visit to a brownstone with blacked-out windows located on 58 Joralemon Street in Brooklyn, which serves as “the world’s only Greek Revival subway ventilator”.
According to a blog called the Willowtown Association, “the ventilator was a private brownstone dating from 1847. The substation was built in 1908 in conjunction with the start of subway service to Brooklyn. As reported in the BKLYN magazine article, the building’s ‘cavernous interior once housed a battery of electrical devices that converted alternating current to the 600-volt direct current needed to power the IRT.'”