The development of chemical warfare around the time of World War I led to the use of tear gas as a weapon by civilian police forces.
The first Earth Day took place fifty years ago, so most people don't remember how it happened or what it accomplished. It's time for a look back.
Giving Stonewall too much credit misses the movement’s growing strength in the 1960s, sociologists note.
The integration of collegiate and professional sports parallels the civil rights movement, but in important ways it was a whole different track.