1. In 1776, the Pennsylvania Evening Post published a copy of the Declaration of Independence, which had been approved by the Continental Congress on July 4. Pennsylvania played a crucial role in the American Revolution, with Philadelphia serving as the temporary capital of the newly formed United States.

2. On July 10, 1900, the Commonwealth of Pennsylvania officially adopted "Pennsylvania" as its official state nickname. The name, which means "Penn's Woods," was chosen to honor William Penn, the founder of Pennsylvania, and the state's extensive forests.

3. In 1934, pioneering astronomer and Western University of Pennsylvania professor James Edward Keeler died. Keeler made many important contributions to the field of astronomy, including discovering a gap in Saturn's rings that is now named after him.

4. On July 10, 1951, the Pennsylvania Turnpike opened to traffic. The 360-mile toll road, which stretches from Ohio to New Jersey, was the first long-distance limited-access highway in the United States and served as a model for similar roads around the country.

5. In 1971, the city of Scranton experienced one of the worst floods in its history. Heavy rains caused the Lackawanna River to overflow, resulting in significant damage to homes and businesses. The event prompted the construction of flood control measures in the city, including the construction of levees and flood walls.