Inside a NYC $80 Million Megamansion: Cold Plunge, Garage Bar, and Wine Cellar

A historical neo-Italian Renaissance carriage house built in 1910 and later transformed into a spectacular residence by former Morgan Stanley CEO John Mack and his wife, Christy, has just hit the market in Manhattan for an astonishing $80 million.The Upper East Side estate once served as a garage and chauffeur's quarters for Singer heir Stephen C. Clark and was later used by Paul and Bunny Mellon as a private garage. The Macks purchased the 15,978-square-foot structure for $13.5 million in 2009 and transformed it into a 20-room residence in 2011.A "no-expense-spared renovation" now features quarter-sawn oak floors, custom wallpapers, bespoke drapery and fabrics, and designer lighting. The lavish residence has climbed its way to the top spot on the week's most expensive homes list.Luxurious amenities include security and staff offices, a 13-seat soundproof theater, a one-car garage doubling as entertainment space, private guest quarters with a full kitchen, and a chef's kitchen with walk-out dining terrace.Other highlights include six fireplaces, a wood-paneled library, a primary suite with dual dressing rooms and marble baths, two soundproof offices, a 6,319-bottle wine cellar with...