A look at more than 50 years of marches in Washington, by the numbers:
1995 — Organized and hosted by Nation of Islam leader Louis Farrakhan, an estimated 850,000 to 1 million* African-American men came together for the Million Man March to rally for unity and revitalization of African-American communities.
2000 — More than 750,000 people gathered on the mall for the Million Mom March, which sought tighter gun control.
2013 — About 650,000 people participated in the March for Life, a rally protesting abortion.
1997 — More than 650,000 people filled the mall for the Promise Keepers march for evangelical Christian men.
2004 — An estimated 500,000 to 800,000 people attended the March for Women's Lives, which supported women's rights and reproductive rights.
2004 — An estimated 500,000 to 800,000 people marched on the National Mall rallying for women's reproductive rights.
1969 — More than 500,000 people marched on Washington to protest U.S. involvement in the Vietnam War.
1993 — About 300,000 people turned out for the March on Washington for Lesbian, Gay and Bi Equal Rights and Liberation.
1981 — About 260,000 people gathered for the Solidarity March, which was held in response to then-President Ronald Reagan's firing of 12,000 air traffic controllers who had gone on strike.
1963 — Between 200,000 and 300,000 people gathered in Washington to rally in support of civil and economic rights for African-Americans and other disenfranchised groups. On the steps of the Lincoln Memorial, the Rev. Martin Luther King Jr. gave his now-legendary "I Have a Dream" speech.
*Crowd sizes for protests on the National Mall used to be estimated by the National Park Service. But after estimates for the Million Man March proved controversial, the service stopped offering attendance figures.