High Quality Content by WIKIPEDIA articles! The Toynbee tiles (also called Toynbee plaques) are messages of unknown origin found embedded in asphalt of streets in about two dozen major cities in the United States and four South American capitals. Since the 1980s, several hundred tiles have been discovered. They are generally about the size of an American license plate (roughly 30 cm by 15 cm), but sometimes considerably larger. They contain some variation on the following inscription: