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Power! (1966-1968): Across America, the call for "Black Power" mobilizes communities for change in strikingly different ways as told through the perspectives of Black Panther Party members, teachers, and politicians. Promised land (1967-1968): Hear leaders and activists reflect on Martin Luther Kings, Jr's crusade to overcome the fragmenting civil rights movement.

Mississippi: is this America? (1962-1964) : Focuses on the right to vote. Tells how the black citizens who had been denied the right to vote stepped forward and demanded a place in the political process. Medgar Evers, Michael Schwerner, Andrew Goodman, James Chaney, and others, died trying to help them.

Little on this earth can withstand the violent fury of an F5 tornado. A churning vortex with winds over 300 miles an hour, these tornadoes create immense swaths of death and destruction in a matter of seconds. But today, experts are exploring the supertwister's complex inner working in bold new ways in the hopes of one day being able to accurately predict the occurrences of tornadoes.

This 8-part series explores how The U.S. Constitution came to be. Program 7: The Constitution in a Changing World1919 - The Supreme Court Limits Free Speech and Freedom of the Press in Schenck v.