"Mystery on Fifth Avenue" is the title of a New York Times article written by Penelope Green in June 2008 about a mystery apartment on Fifth Avenue in New York City. The apartment, a 4,200-square-foot luxury co-op formerly inhabited by Marjorie Merriweather Post and E.F. Hutton, was purchased by Wall Street mogul Steven B. Klinsky and his wife Maureen Sherry for $8.5 million. They hired architectural designer Eric Clough and his firm 212box for the renovation, during which Clough embedded an extensive mystery in the apartment in the form of riddles, ciphers, puzzles, and hidden objects, for Klinsky’s and Sherry's four children. It was done without his clients' knowledge, and they did not discover the mystery until several months after moving in.