Why America Moved Labor Day to September

From strikes and executions to barbecues and sales, how the U.S. buried the radical roots of May Day.

1. The violent birth of May Day
On May 1, 1886, hundreds of thousands of workers joined a national strike for the eight hour day. In Chicago, the fight turned deadly. A bomb went off during a rally at Haymarket Square. Police opened fire. Seven officers and several civilians were killed.

Authorities used the chaos to put the labor movement on trial. Eight radical organizers were convicted with little evidence. Four were executed. One killed himself in jail. The other three were later pardoned by Illinois Governor John Altgeld, who condemned the trial as unjust.