Exploring the music that kept the spirit of the civil rights movement alive following Martin Luther King Jr.'s death.

In the wake of the 9/11 attacks, songs about New York have heightened meaning, while politically-charged country music takes center stage.

A rise in politically-charged songs follows the killings of four Kent State University students during anti-Vietnam War protests.

In the aftermath of Hurricane Katrina, local musicians are joined by international stars for benefit concerts to preserve New Orleans' rich cultural heritage.

See the course of the Cold War through the lens of Berlin, as well as the music that helped sow the seeds of change.

Neil Armstrong and Buzz Aldrin's walk on the moon helps inspire musicians to imagine a cosmic future for mankind.