Striking sanitation workers and their supporters are flanked by bayonet-wielding National Guard troops and armored vehicles during a march on City Hall in Memphis, Tenn., on March 29, 1968, one day after a similar march erupted in violence, leaving one person dead and several injured.

Striking sanitation workers and their supporters are flanked by bayonet-wielding National Guard troops and armored vehicles during a march on City Hall in Memphis, Tenn., on March 29, 1968, one day after a similar march erupted in violence, leaving one person dead and several injured.