1. Pennsylvania Statehood: On April 15, 1783, the state of Pennsylvania officially became a state. This was three years after the signing of the Declaration of Independence and seven years before the ratification of the U.S. Constitution.

2. John Wilkes Booth Captured: On April 15, 1865, John Wilkes Booth, the man who assassinated President Abraham Lincoln, was captured in Virginia. The search for Booth had been ongoing for more than a week, and his capture brought an end to one of the most significant manhunts in American history.

3. Titanic Disaster: The infamous RMS Titanic hit an iceberg on April 14, 1912, and sank into the ocean in the early morning hours of April 15. More than 1,500 people lost their lives in the disaster, including passengers from Pennsylvania.

4. Jackie Robinson Debuted: On April 15, 1947, Jackie Robinson made his Major League Baseball debut, becoming the first African American player in MLB history. He played for the Brooklyn Dodgers against the Boston Braves, and his debut was a pivotal moment in the civil rights movement.

5. American Revolution Battles: Several important battles of the American Revolution took place on April 15. In 1775, the Battle of Lexington and Concord took place in Massachusetts, starting the war. In 1783, the Battle of Cooch's Bridge took place in Delaware, marking the last battle of the conflict.