Abraham Lincoln Brigade; Pittsburgh Veterans for Peace at a march against the Vietnam War on the Washington, D.C. mall in 1967.
Unidentified anti-war demonstrators at a protest on the National Mall in 1967.
A crowd gathers on the National Mall for the "Million Family March" Monday, October 16, 2000.
Tens of thousands people gathered on the Mall during the No War on Iraq National March in Washington, D.C. on Saturday, January 18, 2003.
Peace activists gather during a rally on the National Mall in Washington, D.C., October 25, 2003. Thousands rallied in Washington on Saturday to protest U.S. policy in Iraq, the first major demonstration since President George W. Bush declared an end to major combat in the war on Iraq.
Demonstrators hold a candelight vigil in protesting war against Iraq on the National Mall on Sunday, March 16, 2003.
Thousands of Tea Party activists gather for a "Restoring America" rally at the Lincoln Memorial in Washington, D.C., August 28, 2010. The rally was held on the 47th anniversary of Martin Luther King Jr.'s historic march.
Thousands attend the Rally To Restore Sanity and/or Fear on the National Mall on October 30, 2010 in Washington, DC.
People listen to speakers during the 50th anniversary of the March on Washington at the Lincoln Memorial in Washington, D.C., Saturday, August 24, 2013.