Today it's hard even to imagine a mansion on five green hilltop acres -- an entire city block -- in the middle of bustling Georgetown. But thanks to Martha Washington's granddaughter, her husband, Thomas Peter, and several generations of their caring descendants, such a place still exists. For nearly 180 years, until 1983 when Armistead Peter III died and ownership was turned over to a foundation, curious passersby had to settle for a snoop through the fence. Many still do, but since 1988 Tudor Place has been open to the public.

The neoclassical house, with its distinctive "temple" portico -- a complete circle inserted into the south wall -- was built on a city block acquired in 1805 with $8,000 left to Martha's granddaughter by George Washington. The architect was William Thornton, who also designed the U.S. Capitol, and while alterations have been made over the years, great pains have been taken by each generation to keep the integrity and history of the place, completed in 1816, intact.

Though great men of American history -- from the Marquis de Lafayette to Robert E. Lee -- often visited Tudor Place, at 1644 31st St. NW, living there must have been a burden to its more recent inhabitants, no matter how wealthy and well connected. Visitors can draw their own conclusions as they tour the 14 smallish rooms filled with family and historical memorabilia. They can also enjoy the house's greatest compensation -- serene space in a city -- as they stroll the south lawns or sniff the boxwood and old roses in the formal gardens on the more austere north side.

Four daily tours ($5 donation) are held five days a week, Tuesday through Saturday, but reservations must be made (202-965-0400).