1. On June 21, 1788, Pennsylvania became the second state to ratify the United States Constitution, following Delaware. This pivotal moment in Pennsylvania history helped to create the framework for the nation's government and established the principles of democracy that still guide us today.

2. June 21, 1893, marked the dedication of the Gettysburg National Cemetery, located on the site of the famous Civil War battle that took place in July 1863. The cemetery was created to honor the soldiers who fought and died in the Battle of Gettysburg and serves as a powerful reminder of the sacrifice and bravery of those who served in the conflict.

3. One of the most significant events in Pennsylvania aviation history occurred on June 21, 1924, when Ruth Law, a pioneering female pilot, completed a record-breaking flight from Chicago to New York City. Law's flight demonstrated the growing potential of aviation technology and helped to inspire a new generation of women to pursue careers as pilots and aviation professionals.

4. June 21, 1978, marked the opening of the Gateway Clipper Fleet, a popular Pittsburgh-based riverboat tour company that offers scenic excursions along the Allegheny, Ohio, and Monongahela rivers. The Gateway Clipper Fleet has become an iconic part of the Pittsburgh tourism industry and a beloved institution among locals and visitors alike.

5. On June 21, 2019, the Pennsylvania State Capitol in Harrisburg celebrated its 115th anniversary. Completed in 1906, the Capitol is known for its stunning architecture and impressive collection of historic art and artifacts. The building serves as the seat of the Pennsylvania government and is a must-visit destination for anyone interested in the state's political and cultural history.