A trip through the double doors of the home, built in 1939, gives way to a three-story rotunda set off by a double staircase and crowned by a grand chandelier. [...] a trip throughout the rest of the house, which spans nearly 20,000 square feet, makes it feel like a normal home, with a cage of birds chirping in the sunlight and empty kennels for dogs who are out exercising. [...] when Hatton combed through the digital records of the Greenwich Multiple Listing Service, she found only five listings at or above $30 million since records have been kept electronically -- about 15 years ago. Originally built for $200,000 in 1939, it earned the distinction of the largest residential permit issued by Greenwich's building department that year. "There are very few properties like this, something with six acres on the water on a peninsula like this," said Lurie as she walked into a wood-paneled library on the first floor, where tall windows overlook a putting green and the still blue water of the harbor. "[...] a buyer needs to have the money," she said. "For 1998, that was a very big sale," said Lurie, who added the current owners immediately began a massive renovation, which includes a tennis court, as well as a 4,000-square-foot addition, built in 2000.