"I knew why they chose Rosa" Parks instead of her as a symbol of the civil rights movement, Colvin says. "They thought I would be too militant for them." Julie Jacobson/AP hide caption

itoggle caption Julie Jacobson/AP

President Johnson and Mexican President Gustavo Di­az Ordaz, with their wives, celebrate the dedication of the Chamizal Monument in Juarez, Mexico, on Oct. 28, 1967. The monument signified the international boundary marker between the two countries, designated in 1964. Yoichi Okam/Courtesy of the LBJ Presidential Library hide caption

itoggle caption Yoichi Okam/Courtesy of the LBJ Presidential Library

Studs Terkel circa 1970. Courtesy of Studs Terkel Radio Archive/WFMT hide caption

itoggle caption Courtesy of Studs Terkel Radio Archive/WFMT

Visit Mandela: An Audio History for more on this series. Photo courtesy of Mayibuye/Robben Island hide caption

itoggle caption Photo courtesy of Mayibuye/Robben Island

Democracy demonstrators wave the Burmese flag in August 1988, when millions of Burmese took to the streets. Students led the protests, but were soon joined by civil servants, police, soldiers and ordinary citizens. Courtesy of Gaye Paterson hide caption

itoggle caption Courtesy of Gaye Paterson

Melissa Rodriguez struggled to create a stable life at home for her son in the late 1990s. Today, he's a teenager and together, they've faced many challenges. Radio Diaries (left), David Gilkey/NPR hide caption

itoggle caption Radio Diaries (left), David Gilkey/NPR

In 1996, Josh Cutler took his tape recorder to high school, documenting his effort to live a normal life. Today, he also documents his efforts to live a normal life with a brain that often betrays him. Radio Diaries (left), David Gilkey/NPR hide caption

itoggle caption Radio Diaries (left), David Gilkey/NPR

Frankie Lewchuk had been a high school football star whose picture was in his hometown newspaper every week. Now, after struggling with a crystal meth addiction, he is trying to repair his life. Radio Diaries (left), David Gilkey/NPR hide caption

itoggle caption Radio Diaries (left), David Gilkey/NPR

Joe Richman, founder and executive producer of Radio Diaries, tracked down some of the teen diarists from the 1990s and got updates on their lives. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

Juan recorded his first diary at 18. He now lives in Colorado and is married with three children. Radio Diaries (left), David Gilkey/NPR hide caption

itoggle caption Radio Diaries (left), David Gilkey/NPR

Amanda as a teenager (left). She now lives in Manhattan and works as a massage therapist. Radio Diaries (left), David Gilkey/NPR hide caption

itoggle caption Radio Diaries (left), David Gilkey/NPR

Are you the next Radio Diaries teen diarist? M Mujdat Uzel/iStockphoto.com hide caption

itoggle caption M Mujdat Uzel/iStockphoto.com

During his inaugural address on Jan. 14, 1963, newly elected Alabama Gov. George C. Wallace vowed "segregation now, segregation tomorrow, segregation forever." Bettmann/Corbis hide caption

itoggle caption Bettmann/Corbis