Today in history

May 4

1886
At Haymarket Square in Chicago, a labor demonstration for an eight-hour workday turned into a riot when a bomb exploded. A mass meeting had been called for that night when a large force of 176 police officers arrived with a demand that the meeting disperse. Someone, unknown to this day, then threw a bomb at the police. In their confusion, the police began firing their weapons in the dark, killing at least four in the crowd and wounding many more. Several police died (only one by the bomb), the rest probably by police fire.

1961
A group of Freedom Riders left Washington, DC for New Orleans in a first challenge to racial segregation on interstate buses and in bus terminals; it was organized by the Congress of Racial Equality (CORE).

1970
Ohio National Guard troops opened fire on anti-war protesters at Kent State University, killing four students and wounding nine others. The previous day, President Nixon had announced a widening of the Vietnam War with bombing in neighboring Cambodia. There were major campus protests around the country with students occupying university buildings to organize and discuss the war and other issues.

1989
30,000 students march for democracy to Tienanmen Square, Beijing.

1993
Kampuchea (Cambodia): Dhammayietra, walk for peace, to Phnom Penh, begins, Siem Reap.