Washington is a city built to a plan, which is rare in the United States. In 1791 the French-born engineer Pierre L'Enfant laid out a capital of wide avenues and open parks, and the long green lawn he imagined became the National Mall. The government moved in during 1800, the British burned the Capitol and the White House in 1814, and both were rebuilt. Today the Mall is a two-mile (3 km) lawn with the nation's memorials at one end and its museums down both sides, and most of them cost nothing.
The catch is that free doesn't mean unplanned. Some museums need a timed pass, the Capitol and the Library of Congress want a reservation, and a White House tour is something you request weeks ahead through a member of Congress. The city is also much more than the postcard. Across the river is Arlington, on the other side of the Mall is a Black cultural history that runs from U Street to a museum that took decades to build, and the Ethiopian restaurants here are among the best outside Ethiopia. Five days is the right length: it covers the Mall properly, adds Capitol Hill, Arlington, Georgetown and U Street, and leaves a day for Mount Vernon.
Day one is the memorials and the White House, day two the museums on the Mall, day three Capitol Hill, the Library of Congress and the waterfront, day four Arlington, Georgetown and U Street, and day five a day trip to Mount Vernon and Old Town Alexandria. We recommend starting on a Tuesday. The Library of Congress is closed on Sundays and Mondays, and White House tours run Tuesday to Saturday, so this order keeps booked visits on open days. Read the United States country guide for visas, money and the rest of a longer trip.