The Pentagon.
Because it has five sides, five floors (above ground), five ring corridors per floor, and a five-acre central plaza. Pentagon is the name for a five-sided polygon. Also, The Pentagon is in Virginia, not Washington DC.
A 5-sided polygon is a pentagon. An example is the huge military office building in Arlington, VA (near Washington DC) which is called the Pentagon. It has an only slightly irregular five-sided design.
The Pentagon is located near Washington DC in Arlington, Virginia (United States of America) and is called the pentagon because it is a five sided building.
Washington, DC
Do you mean the capitol building in Washington DC?
The United States Capitol Building. Not the white house, but the building with the big dome in Washington DC. The US Capitol in Washington DC.
An obelisk. The Washington Monument in Washington DC is an example.
the Pentagon....in Washington dc
Washington DC
The US Capitol Building in Washington, DC
The capital building in Washington DC was designed by Dr William Thornton. The plan had three sections to house the House of Representatives, Congress as well as the main building.