Bubble gum, Vaseline, zippers, Groundhog Day, Little League baseball, the state police force, the gas station... Today, people across the country-and the world-take these things for granted, but we have the inventiveness and skill of Pennsylvanians to thank for all of them. From the amazing and amusing to the famous and fantastic, Pennsylvania Firsts shows you why Pennsylvania so richly deserves its reputation as the "keystone" of our nation!