It started 132 years ago in the United States, in New York City, as a dedication to the the achievements of American workers.  Since then the US has recognized it annually, as a national holiday, and established the date as the first Monday in September.  Most of us celebrate by way of time off from work, backyard barbecues, horseshoes, shopping (bargains) and in other unique ways.  How ever you decide to celebrate, enjoy your day!

Here's a glimpse of the actual history, from the U.S. Department of Labor Website: 

"Labor Day, the first Monday in September, is a creation of the labor movement and is dedicated to the social and economic achievements of American workers. It constitutes a yearly national tribute to the contributions workers have made to the strength, prosperity, and well-being of our country."

"The first Labor Day holiday was celebrated on Tuesday, September 5, 1882, in New York City, in accordance with the plans of the Central Labor Union. The Central Labor Union held its second Labor Day holiday just a year later, on September 5, 1883."