The Upper East Side's Harkness Mansion was getting pretty lonely as Manhattan's only $50 million townhouse?lying awake in bed, never changing clothes, making a habit of having one glass of chardonnay too many?so Seagram's heir/Warner Music boss Edgar Bronfman, Jr. decided to do something about it. Bronfman paid just $4.375 million for his 31-foot-wide East 64th Street townhouse (top left) in 1994, and the Observer's Max Abelson reports today that he sold it for clear of $50 million, although less than the Harkness' final tally of $53 million (after all, why make a scene?). Bronfman, suddenly homeless, plunked down nearly $20 million of those winnings on this five-bedroom spread at 1040 Fifth Avenue (top right), a Candela building not quite as Candela-y as 740 Park or 834 Fifth Avenue, and just #7 on CityRealty's Fifth Avenue Top 10. But hey, Jackie O. lived there, so we're not talkin' tenements or anything.