For Manhattan’s jet-set crowd, the 2010s are starting to look an awful lot like the 1900s.

New York’s upper crust are embracing a return to the Gilded Age, moving out of their fancy penthouses, co-ops and lofts and into opulent single-family mansions. From Aby Rosen’s quest to build the largest private mansion on Park Avenue to Jared Kushner’s conversion of three former Brooklyn Law School buildings into single-family townhouses—the most affluent buyers are now on the hunt for New York’s ultimate trophy prize.

Once a much larger proportion of Manhattan’s housing stock, mansions dominated Fifth Avenue—known as Millionaire’s Row—through much of the mid-to-late 19th century. But, by the early 20th century, luxurious apartment buildings began to quickly replace many of these single-family structures, as wealthy New Yorkers favored the ease associated with maintaining a co-op apartment.

Now, it seems, the pendulum is swinging the other way, as more ultra-affluent buyers shun the headaches involved with board approval, opting for a more private alternative. And, in the search for gargantuan single-family mansions, wealthy homebuyers are not only scooping up existing townhouses, they are also buying up and converting apartment houses, commercial buildings, consulates and private schools.

Here is a look at some impressive mansion conversions in New York City:

GKV Architects will handle the renovation seen on the right

27 CHRISTOPHER STREET

Built in 1911, the landmarked 19,000-square-foot, four-story building at 27 Christopher Street in the West Village is the former headquarters of New York Foundling, a nonprofit social services agency, which sold the brick-and-limestone building earlier this month for $45 million to a buyer who intends to convert it into a single-family residence. One of New York’s oldest charities, New York Foundling purchased the building—which previously operated as a Catholic school and nursing school—for only $3 million in 2002. The landmarked neo-Classical building measures an impressive 60-by-70-foot wide and features 3,980 square feet of outdoor space.

Tracy Mansion. Image courtesy of Halstead

THE TRACY MANSION

Located at 105 Eighth Avenue in Park Slope, Brooklyn, the Tracy Mansion was built in 1912 for the founders of M. & J. Tracy, a tugboat and barge operator. Designed by Frank J. Helmle, the 50-foot-wide, neo-Classical structure features impressive architectural details, including fluted Corinthian columns and bronze front doors. Interior flourishes include dramatic staircase, book-matched flame Honduran mahogany and butler’s pantry. In 1969, Anil Kumar Sinha bought the home and, with his wife Hannah, operated a Montessori school there. It is now on the market for $15 million.

47 East 3rd Street before it was renovated (left); Post-renovation (right). Images via Evergreen Review and Property Shark

47 EAST 3RD STREET

Before it was a 60-room mansion, 47 East 3rd Street was a tenement building that housed 15 rent-stabilized units. Following a 10-year quest to empty the building of its rent-regulated tenants, the owners settled with the remaining residents, agreeing to pay between $75,000 and $175,000 per unit. In 2012, following a 2 ½-year gut renovation, Alistair and Catherine Economakis moved into the newly minted mansion, which features interior elements such as double-height living room with waist-high glass wall, recycled wooden beams over the living room fireplace, and a “wrestling room” with red-and-black padded mat and a wall of mirrors.

7 East 96th Street. Image courtesy of the Corcoran Group

7 EAST 96TH STREET

Built in 1912 by Ogden Codman, the 40-foot-wide, French Renaissance château at 12 East 79th Street has been home to the Manhattan Country School since 1966. One of only a few Manhattan properties with a driveway, courtyard and private garage, the 15,142-square-foot building features limestone façade, slate roof, central marble staircase, circular dining room, oak-paneled ballroom, huge oak double-coach doors, and Juliet balcony, among other original details. Listed at $23 million cash-only, the property sold for much higher following a bidding war. The buyer is expected to spend millions more renovating the property prior to the move.

PHILIP LEHMAN MANSION

Located at 7 West 54th Street, the Philip Lehman Mansion is a Beaux Arts-style mansion constructed in 1889 for Philip Lehman, son of Lehman Brothers co-founder Emanuel Lehman and his wife. Landmarked in 1981, the six-story mansion, which includes a top-floor glass penthouse addition, was previously used as a commercial office space. Following a meticulous renovation by Lehm Holdings, the 16,000-square-foot property was sold late last year for $40 million. Located across from the Metropolitan Museum of Art, the mansion was designed by John H. Duncan and features limestone façade and triple circular windows on the top floor.