This undated photo shows Rosa Parks riding on the Montgomery Area Transit System bus. Parks refused to give up her seat on a Montgomery bus on Dec. 1, 1955, and ignited the boycott that led to the end of legal segregation in public transportation. AP hide caption

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Young people attend a political rally before the recent Jefferson-Jackson dinner in Iowa. Energizing young voters may be a challenge for presidential candidates ahead of 2016. Charlie Neibergall/AP hide caption

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Desiree Griffiths of Miami holds up a sign reading "Black Lives Matter" during a protest over the deaths of Michael Brown and Eric Garner. Lynne Sladky/AP hide caption

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A protester stands in front of police vehicles with his hands up during a demonstration in Ferguson, Mo., where in August 2014 a white police officer shot and killed an 18-year-old black man. Justin Sullivan/Getty Images hide caption

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Carlos Santana visits NPR for an interview about his new memoir The Universal Tone: Bringing My Story to Light. Maggie Starbard/NPR hide caption

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NPR's Michele Norris on Morning Joe. She joined the MSNBC program on the 50th anniversary of the March on Washington. screenshot from MSNBC.com hide caption

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Use #NPRAspen to share your ideas about improving education and learning. NPR hide caption

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