It wasn't always about the grilling and Slip'N Slide.

In fact, that last glorious slice of summertime that Labor Day has come to represent masks the overlooked turbulent history that led to its establishment in the first place.

Nineteenth Century America was a time of rapid industrialization. Many of the nation's urban centers were bursting at the seams, attracting a flood of poor immigrants desperate for work, but vulnerable to exploitation. Growing labor unrest led to a string of major strikes and protests, with workers demanding higher pay, safer working conditions and the right to unionize. The demonstrations often sparked violent clashes with police and private company security forces.

The unrest, though, proved fruitful. It ultimately led to major improvements for millions of workers, ushering in an era of new labor regulations that included the establishment of an 8-hour workday and laws prohibiting child labor. The reforms also gave rise to a prolonged period of burgeoning union membership, increased wages and a notable rise in the ranks of America's middle class.