Built in 1930 and incorporated in 1952, this full-service prewar co-op on Park Avenue between 78th and 79th sits in Lenox Hill’s Gold Coast. The 19-story building has 36 units and offers white-glove amenities like a 24-hour doorman, elevator operator, squash and basketball courts, fitness center, private storage, and backup generator. It allows 50% financing and charges a 2.5% flip tax.