May 10

Thanks to an army of thousands of Chinese and Irish immigrants, who laid 2,000 miles of track, the nation’s first transcontinental railway line was finished by the joining of the Union Pacific and Central Pacific lines at Promontory Point, Utah – 1869
And this: May 10, 1876 - The Centennial Exposition, a display of America’s achievements in industry, science, agriculture and the arts, opened in Philadelphia. This paean to progress stood in sharp contrast to the shantytown just outside its gates, where the unemployed and homeless had yet to benefit from the industrial capitalism. Seven years earlier, on May 10, 1869, a golden spike was driven into the track at Promontory Point, Utah, connecting the Union Pacific and Central Pacific railroads and creating the transcontinental railway system.
U.S. & Canadian workers form Western Labor Union. It favors industrial organization and independent labor party politics - 1898
A federal bankruptcy judge permits United Airlines to legally abandon responsibility for pensions covering 120,000 employees - 2005
Labor history found here:
http://www.unionist.com/today-in-labor-history & here:
http://www.workdayminnesota.org/index.php?history_9_05_10_2011