For Kids: May Day probably started in ancient Rome or possibly ancient Greece. The holiday originally celebrated the return of spring. Today, in just about every country in the world except for the United States, workers are recognized on May Day, the first day in May.
The United States does not recognize May Day as a federal holiday. Instead, workers are honored on Labor Day, which falls on the first Monday in September each year. Labor Day is a federal holiday. It is a day we honor our work force. It is simply a day off from work with no religious significance at all.