National Mall ~ http://www.nps.gov/nama
The National Mall's origins are as old as the capital city itself. The open space and parklands envisioned by Pierre L'Enfant's plan, which was commissioned by George Washington, created an ideal stage for national expressions of remembrance, observance and protest.
The National Mall resources include the 2,000 American elms which line the Mall and the 3,000 internationally renowned Japanese cherry trees which grace the Tidal Basin. Gardens that are botanical showplaces display thousands of tulips, pansies and annuals in over 170 flower beds, and 35 ornamental pools and fountains range from the simple to the sublime. This impressive mingling of natural and cultural resources has made our Nation's Capital one of the most heavily visited and photographed places in the world.