The spectacular observation lounge overlooking the Hoosic River and Taconic mountains at the western end of Building 6 was the product of engineering, imagination — and money. Two stories high with a balcony and a 21-foot-high, 12-foot-wide window, it is both a place to rest and the scenic climax of a tour through the museum, a trek that can now amount up to 4 miles. It wasn’t always so. “The Prow,” as it’s called, was originally the top two floors of the three-story, post-and-beam-style mill, with a clutter of interior columns, a stairway and two small windows on each floor looking west. Read more about Mass MoCA’s dramatic design >>