bought the house from his billionaire friend Edgar Bronfman, Jr., who paid just $4.375 million for the 31-foot-wide house in 1994. And because one $50M house is never enough, Blavatnik is reportedly in contract to drop $80M on the penthouse of 834 Fifth, which will be the most expensive co-op ever sold. [Photo via PropertyShark.]

In November, financier Leon Black dropped $50.25 million on the former Knoedler & Company art gallery at 19 East 70th Street, with plans to turn it into a single-family home. And according to permits filed with the Department of Buildings, that appears to be what he's doing. The Renaissance mansion sold for $35 million in 2010 to developer Christian Candy, who got the ball rolling on the renovation, but when it was reported that Black bought the place, the house still needed another $20 million worth of work.

After bankrupting the Los Angeles Dodgers in 2012, billionaire Frank McCourt consoled himself by buying a $50 million co-op on Fifth Avenue. The full-floor apartment was previously owned by investor David Hamamoto, who owned the place for 14 years and spent two of those years renovating it with architect Thad Hayes. The result got the Architectural Digest treatment.

The month after unit no. 80 in One57 sold, the full-floor apartment on the floor below also went, for $50,916,000. The buyer also shielded him/her/them/itself behind an LLC called, boringly, One57 79 Inc. So commonplace was this +$50 million sale that it was barely even reported.

The 18,000-square-foot mansion at 113-115 East 70th Street has been featured in the New Yorker and New York Magazine, Harper's Bazaar, Vogue, and Elle Decor; needless to say, it is gorgeous. Former Coach creative director Reed Krakoff and his interior designer wife Delphine are responsible for making the place so beautiful, but for reasons that plebians would never understand, they decided to move on. The house never formally listed, but it sold in an off-market deal last February for $51 million. [Photo via PropertyShark.]

Following the Plaza Hotel's partial condo conversion, an entity known as Plaza 7 Apartment LLC bought six individual units on the seventh floor for a combined $51,539,180, possibly combining them into one mega-apartment...or not. It's not exactly clear, but reports from the Observer and ABC at the time seemed to suggest that the sale was of one large apartment.

Back to One57, where one of the 11 floor-through simplexes closed for a hair under $53 million ($52,952,500, to be exact) this past November, prompting broker Michael Graves to inform the Times that, "Living on a full floor at One57 is probably the closest thing to being a king in the 21st century." The buyer was shielded by an LLC known as Lapus NY Inc., with a Pasadena, California address.

Art dealer and gallery owner Larry Gagosian paid $36.5 million for East 75th Street's Harkness Mansion in August 2011, taking it off the hands of investor J. Christopher Flowers, who paid a record-setting $53 million for the 50-foot house, once home to Rebekah Harkness's personal ballet company, in 2005. (Real nice investing there.) Flowers spent another million to gut the place before turning around and unloading it for a massive loss. Gagosian has been undertaking a massive and secretive renovation ever since. [Photo from October 2014 via Google Streetview.]

Socialite Denise Rich sold her seven-bedroom, eleven-bathroom spread in The Parc V at 785 Fifth Avenue for $54 million to business magnate David Geffen in November 2012. Funny story: Rich dumped the pad after renouncing her US citizenship to save on taxes, and Geffen bit despite earlier disputes involving plumbing between the two. Word in 2012 was that Geffen was planning a major renovation and overhaul that would take about two years, meaning he may have finally moved in some time just last year.

Here's yet another One57 closing from the momentous real estate-crazed year of 2014. An 85th-floor apartment officially sold for $55.6 million. It has four bedrooms, four bathrooms, amazing views (of course), and marks the building's third-highest sale to date. Like so many units in the megatower, it was purchased behind the veil of an LLC. A 2012 Times story, though, has more intel: "The 6,240-square-foot apartment was bought by an American who already owned 'some of the best real estate in the world,' including two 'very significant' places in New York." Anyone care to hazard a guess?

Despite reports that 57th Street megatower One57 is having trouble finding buyers for its remaining units on lower floors, high-up apartments that sold and closed in 2014 take up a lot of spots on this list. After the number-one eye-popper, there's this sale on the 82nd floor, where an apartment sold to Ridgewood 57 Inc. for 56,079,298.25.

Once-troubled tower One Madison now counts celebrities like Gisele Bundchen and Tom Brady along its owners. Add to that magnate Rupert Murdoch, who bought the bonkers triplex penthouse in August; the deal closed in March. The 6,850-square-foot sponsor unit, a 5BR/5.5BA with a wraparound terrace and statement staircase, ultimately raked in $43 million. At the same time, Murdoch bought a three-bedroom unit that takes up the 57th floor, bring the total cost of his purchase to $57 million. Presumably for visiting guests, or pets, or household staff, or anyone else who can't fit in the triplex above.

Egypt's richest man held the record for purchasing the city's most expensive co-op—2014's second most expensive sale—for about three months. After a bidding war, construction magnate (and billionaire, of course) Nassef Sawiris spent $70 million on a penthouse at 960 Fifth Avenue formerly owned by the late Edgar Bronfman, Sr. Bronfman passed away in December of last year, and his full-floor, 16-room apartment officially listed for $65M in March. Sawiris will enjoy five bedrooms, 8.5 bathrooms, a ginormous wraparound terrace with 100-feet of frontage along Central Park, and four staff rooms on the floor below. He'll probably need that built-in safe, too. The purchase unseated a $54 million buy further south on Fifth Avenue back in 2012. Small change, these days. Then it was unseated itself by Englander's buy, below. Whew.

And now, the most expensive co-op sale ever recorded, which hit record books in 2014. In August, after a fierce bidding war, billionaire and Millennium hedge fund guru Israel "Izzy" Englander emerged victorious and officially paid a whopping $71,277,500 for a palatial duplex at the world's richest apartment building. The 18-room apartment at 740 Park Avenue was formerly occupied by France's ambassador to the UN, which hit the market in April asking a "mere" $48 million. The in-debt nation paid something like $600,000 for the place back in 1979. And now Englander, who already lives in the building, has a "pied-a-terre" for when his children and grandkids come to town. The most priciest win-win ever?

New York City's second-priciest real estate transaction belongs to the penthouse of 15 Central Park West, which traded between Citigroup head Sanford Weill and the 25-year-old daughter of fertilizer king Dmitry Rybolovlev in 2012 for $88 million. Ekaterina Rybolovlev calls home the 6,700-square-foot, four-bedroom apartment that Robert A.M. Stern redesigned at the behest of the Weills. Fan-cy. [Image via AD.]