1. On February 18, 1735, Pennsylvania founder and politician William Penn died. Penn had established the colony of Pennsylvania as a haven for religious freedom and tolerance, and his legacy continues to influence the state to this day.

2. In 1861, the Pennsylvania General Assembly authorized the formation of the 93rd Pennsylvania Volunteer Infantry Regiment, which would go on to serve in the Union Army during the Civil War. The regiment fought in numerous battles, including Antietam and Gettysburg.

3. February 18, 1879 marked the birth of American composer, conductor, and pianist Wallace Goodrich, who was born in Germantown, Pennsylvania. Goodrich was known for his contributions to the American orchestral repertoire, and held positions with the Boston Symphony Orchestra and the New England Conservatory.

4. In 1929, the Saint Valentine's Day Massacre took place in Chicago, Illinois, but a key figure in the incident had ties to Pennsylvania. The massacre was orchestrated by infamous gangster Al Capone, who had previously done business with bootleggers in Philadelphia and Pittsburgh.

5. Finally, on February 18, 1979, snow fell across eastern Pennsylvania, resulting in the state's largest-ever snowstorm. Dubbed the "President's Day Storm," the blizzard dumped up to 30 inches of snow in some areas, causing widespread transportation disruptions and power outages.