When wealthy leather merchant and special police deputy Julien Stevens Ulman married Gertrude Oldfield Barclay in April of 1901 (their engagement made the society pages), he was tasked with finding a home in Manhattan for the couple. According to DiM, "speculative builder J. C. Lyons began advertising his still-unfinished mansion" on 81st and Madison—a “palatial dwelling with 34 rooms, an electric passenger elevator, dumbwaiter, intercommunicating telephones, electric lighting and indirect steam radiation." By late 1902, it was ready for a family, and the Ulmans moved into the 24 East 81st Street home right away.

Following Julien Ullman's death, the family sold the home in the 1920s to archaeologist Hagop Kevorkian, who in turn sold it to The Bentley School in 1941—they paid $125,000. Since being built, it has not changed hands many times, and currently it's been in the same family for the past four decades—the owners are said to be "affiliated with development company Centaur Properties," and reportedly they're about to sell. According to the Daily News, it could go for $70 million, making it the most expensive townhouse in Manhattan. While it's currently separated into six residential units (and has been since 1946), the new buyer could convert it back into a supermansion.

If you want to see the inside for yourself, you can do that—just make reservations at Crown, which is housed on the main floor. And click through for a look at what the interior looked like when the Ullmans lived there.