New York’s Daily News recently asked Martha what her biggest real estate regret has been. She wasted no time in answering: the Duke Semans mansion at 1009 Fifth Avenue, which sold for $40-million to Russian real-estate czar Tamir Sapir in January, 2006. Martha told the Daily News that she was ready to bid on the seven-story, 20,000 square foot house but decided to postpone it in lieu of a much-needed vacation. When she got back, however, the house had already been sold. She says she deeply regrets that now:

“That was going to be my place in New York. It had stairs, and I love stairs. The dogs could run up and down them. I could entertain before events at the museum. I could have musicians playing. I almost cry every time I go by.”

Martha has a Fifth-Avenue pied-a-terre not far away from the Semans mansion for city entertaining, but it is a mere fraction of the size, with a single bedroom and a narrow, galley kitchen. (You can read more about her apartment through the “Martha’s Homes” link at the side.)

Built in 1901, the facade of the Semans house faces Fifth Avenue and runs down the side of East 82nd Street. It includes two outdoor terraces and offers amazing rooftop views of Fifth Avenue & Central Park. It is located directly across from the Metropolitan Museum of Art and features 11 marble fireplaces, three elevators and a sweeping brass-and-wrought-iron staircase. One of the bathrooms is said to be finished entirely in black marble. With its 12-foot high ceilings, gold-leaf trimmed fixtures and intricate plaster friezes, the property is a living piece of architectural history.

Martha might take a little sigh of relief, though. The house needed a further $10-million in renovations to convert the mansion to a single residence again, which had been previously divided into three apartments.

Andrew’s note: Some things aren’t meant to be. Personally, I don’t think this place is really a ‘Martha house.’ It’s too ostentatious, too palatial to be one of Martha’s. I don’t see her personality when I look at it. Martha’s more about rusticated elegance than black marble and gold.