A system of roadside signage developed by the Pennsylvania Department of Highways just after the First World War, the iconic Keystone Markers could be found at the entrance to every Pennsylvania town, borough and city.
Keystone | Magik Markers | Keystone Cops | Keystone Studios | Keystone Cup | Keystone Pipeline | Keystone Lake | Keystone, Colorado | The final form of Braille's alphabet, according to Henri (1952). The decade diacritics are listed at left, and the supplementary letters are assigned to the appropriate decade at right. Characters are derived by combining the diacritic on the left with the basic letters at top. "(1)" indicates markers for musical and mathematical notation. Parentheses and quotation marks follow English Braille | Nevada Historical Markers | List of Pennsylvania state historical markers | Keystone State Boychoir | Keystone, South Dakota | Keystone Pathfinder | Keystone Oaks High School | Keystone National High School | Keystone Motor Company of Philadelphia | Keystone (limestone) | Keystone Korner | Keystone, Island County, Washington | Keystone College | Keystone Centre | Keystone Camera Company | Keystone Aircraft | Keystone | Gulf Keystone Petroleum | Crozer-Keystone Health System |