International Workers' Day, or May Day in other countries, is rooted in the labor movement of the late 19th century, which gained momentum after the Haymarket Affair. This happened in Chicago in ...
a deadly clash between striking workers and federal troops in Chicago in 1877 The Haymarket Affair, a bombing during a peaceful worker’s rally in Chicago in 1886 The Thibodaux Massacre ...
Across the pond, the day is noted for its connection to the Haymarket Affair in 1886, in which 10 people were killed in Chicago at a protest aimed at securing an eight-hour working day.