The National Mall is the two-mile green corridor that runs from the Capitol Building west to the Lincoln Memorial, with the Washington Monument at its centre. It is not a shopping mall — it is the civic core of the country, lined on both sides by the Smithsonian museums and flanked by reflecting pools, war memorials, and the most visited stretch of public land in the United States.
On any given day the Mall holds joggers, tourists, school groups, political protests, and the occasional kite. All the Smithsonian museums along its flanks charge no admission. The monuments are open day and night. Plan at least two full days if you want to do more than walk the length of it — each Smithsonian museum alone could occupy a full afternoon.