It was the happening place to be in the late 1970s, the disco capital of the world. The world’s biggest stars from Jackie Kennedy Onassis to Mick Jagger were his guests. Former Studio 54 co-owner and longtime real-estate developer, Ian Schrager, has listed his New York City West Village apartment for $9.95 million. With big views of the Hudson River and city skyline, the Richard Meyer-designed building has been a longtime hot spot for celebrity residents such as Nicole Kidman and Calvin Klein.