1. In 1778, a surprise attack led by British soldier Captain Henry Bird on Fort Hand, which was located in present-day Franklin County, Pennsylvania, set the stage for the first recorded aerial bombardment by hot air balloon. After setting up a prototype balloon made of paper and silk inside the fort, Patriot soldiers under the command of Lieutenant Colonel George Morgan loaded it with incendiary devices and launched it over the oncoming British forces as an improvised weapon of last resort.

2. On the same day just one year later, in 1779, Continental Army Brigadier General Anthony Wayne led a successful raiding party against a British supply train near Middle Creek in what is now Snyder County, Pennsylvania. The raid not only helped to disrupt British operations in the area, but also served as a morale boost for the American troops.

3. In 1840, Pennsylvania became the first state to recognize Arbor Day, which is celebrated to this day as a day dedicated to the planting and care of trees. The idea originated with J. Sterling Morton, a Nebraska politician and editor, who proposed that a special day be set aside for the planting of trees in his home state.

4. On April 2, 1968, the day after the assassination of Martin Luther King Jr., unrest and violence erupted in cities across the United States, including Philadelphia. Over two days of escalating rioting, 13 people were killed, hundreds were injured, and thousands were arrested.

5. In 2012, the Pennsylvania State Police and the FBI announced the identification of a new suspect in the infamous 1998 murder of Pennsylvania State University student Kirstin Snyder. DNA evidence linked the suspect, who was a Pennsylvania man and had never been a suspect in the case before, to the crime scene. The arrest marked a rare instance of a cold case being solved through the use of modern forensic techniques.