Casa Sin Nombre, Palm Beach, FloridaOwner: Columbia University, bequeathed by the late John Kluge
For Sale: $59 million
Once dubbed the "richest man in America," John Kluge's former Palm Beach estate is still on the market for a remarkable $59 million. Kluge donated the sprawling property (four acres!) to his alma mater Columbia University as part of a $400 million gift in 2007. The school put it on the market in 2011, according to the Sun Sentinel. The property includes two main houses as well as three staff or guest houses. The Ocean House was designed by famed architect Addison Mizner in 1921, and features a loggia, formal dining room, library, and carved-stone fireplace.