“Unlike anything offered in Manhattan” is a rather strong statement, but the circular living area of this duplex on upper Central Park West is certainly one of the city’s most unique spaces. (After all, how many rooms are measured by diameter?) Located in one of the landmark building’s turrets, this open living/dining space measures 1,100 square feet — and 37 feet across — and features “spectacular” cathedral ceilings that rise to 37 feet. Elsewhere in the condo’s 5,317 square feet are four bedrooms, six bathrooms, a library, a den and a “gourmet” eat-in kitchen with a “wall of windows” facing the park. Agents: Deanna Kory and Karen Kelley, The Corcoran Group, 212-937-7011 and 212-875-2879