Harriet Tubman, on the far left holding a pan, poses with a group of people whom she helped escape from slavery in the late 19th century. Bettmann / Bettmann Archive
Educator and reformer Booker T. Washington talks to a crowd at the dedication of a Mississippi cotton seed mill in 1899. Library Of Congress / Getty Images
Botanist George Washington Carver works in his greenhouse in this undated photograph. Bettmann / Bettmann Archive
Elizabeth Eckford of what became known as "The Little Rock Nine" is followed and threatened by an angry white mob on her way to class, as one of the first black students to attend classes at Little Rock Central High School in Little Rock, Arkansas, 1957. Bettmann / Bettmann Archive
Participants in Civil Rights Protest in April, 1963 in Washington, D.C. Library of Congress.
National Guard troops block off Beale Street in Memphis as civil rights marchers pass by on March 29, 1968. It was the third consecutive march held by the group in three days. Dr. Martin Luther King Jr., who had left town after the first march, would soon return and be assassinated. Bettmann / Bettmann Archive
American sprinters Tommie Smith and John Carlos raise their fists in a Black Power salute at the 1968 Olympic Games in Mexico City. The move was a symbolic protest against racism in the United States. Smith, the gold medalist, and Carlos, who took bronze, were subsequently suspended from their team for their actions. Anonymous / AP
Lauryn Hill poses with her five Grammys for her album The Miseducation of Lauryn Hill, at the 41st Annual Grammy Awards in 1999. Sgranitz / WireImage