1. In 1837, the Pennsylvania legislature passed a law creating the Philadelphia and Reading Railroad Company, one of the earliest and most successful of its kind in the United States. The company would go on to build over 1,100 miles of rail lines throughout Pennsylvania and beyond.

2. On March 6, 1857, the U.S. Supreme Court issued its infamous Dred Scott v. Sandford decision, which held that African Americans could not be considered citizens of the United States and therefore had no legal right to sue for their freedom. The case would become a lightning rod for the growing abolitionist movement and ultimately helped spark the Civil War.

3. In 1882, a devastating flood swept through Johnstown, Pennsylvania, killing over 2,200 people and causing millions of dollars' worth of damage. The disaster remains one of the deadliest floods in American history and led to renewed efforts to regulate waterways and prevent future flooding.

4. On March 6, 1944, a fire broke out at the Port Chicago Naval Magazine in California, killing over 300 people, mostly African American sailors who were loading ammunition onto ships. The tragedy highlighted the unsafe working conditions and racial inequities that existed in the military during World War II and helped spark protests and reform efforts.

5. In 1967, the Allegheny County Transit Authority (ACTA) was created to oversee the regional public transportation system in Pittsburgh and its suburbs. Today, the agency operates buses, light rail trains, and other modes of transit that serve over 200,000 riders each day.