While Labor Day has become known as a day for back to school shopping, BBQ's and the end of summer, the history of the holiday is far different.

FOX's Jessica Rosenthal reports:

Labor Day is an extension of May Day which began after the Haymarket Affair in Chicago in 1886. Workers were protesting for an eight hour day when someone lobbed an explosive at police. The cops opened fire, seven officers died that day and four civilians did as well. But this began the holiday to honor workers.

Professor of History and Sociology at Binghamton University Melvyn Dubofsky said trade unions came together to form the American Federation of Labor. They knew workers rights had become associated with socialism around the world, and:

(Dubofsky) "Did not want to be associated with something not respectable."

So they moved Labor Day away from May Day to the first Monday in September. After other worker strikes, President Cleveland made it an official holiday in 1894. By the early 1960's, nearly a third of workers were members of unions in this country. Now just 10 percent are:

(Dubofsky) "A lot of working people no longer have the security and stability they once had."

Dubofsky says a lot of what workers now have in terms of wages, medical coverage and aid holidays are because of labor unions.

Jessica Rosenthal, FOX News.

Follow Jessica Rosenthal on Twitter: @JessicaFOXNews