For one of the best views of Washington, D.C., head to the Old Post Office Museum and Tower any day from 9 a.m. to 4 p.m. Run by the National Park Service, admission is free. You'll walk through a hall with a tiny exhibit about the history of the 1899 old main post office before taking two wheelchair and stroller accessible elevators to the 270-foot observation deck where you can see incredible views of D.C.'s landmarks. Park along Constitution or Madison Drive or take the nearby Federal Triangle Metro. read more