Labor Day and May Day emerged from the movement for a shorter workday in industrial America

It took more than a century for Chicago's Haymarket Square to get this memorial to the historic labor strife that occurred there. Jeffrey Sklansky

Most of the world observes International Workers’ Day on May 1 or the first Monday in May each year, but not the United States and Canada. Instead, Americans and Canadians have celebrated Labor Day as a national holiday on the first Monday in September since 1894, 12 years after the first observance of Labor Day in New York City.

The celebrations aren’t the same.