The modernized, Federal-style townhouse in Society Hill is said to have the country's largest concentration of original 18th- and early 19th-century residential architecture. The listing calls the home "a modern gem of American history."
The four-bedroom, four-bathroom home has been renovated from top to bottom to create an open floor plan -- not an attractive option for early American homeowners, because it would have been a bear to heat. The house now features an elevator, rooftop deck, sunken hot tub, and cherry kitchen cabinets. There's also a walled garden on the ground level and a New Orleans -- style porch on the second level.
Property records show the current owners bought the townhouse for $1.9 million in 2007.
And here's your presidential history lesson for the day: According to Montpelier.org, Dolley Payne Todd, a 26-year-old widow, married 43-year-old Congressman James Madison in 1794. The couple, who reportedly were inseparable, spent their first years of married life in the Philadelphia house, from 1794 to 1797. The man known the "Father of the Constitution" went on to become the U.S. president in 1808.