Visualization of the invisible
The 20th century was the century of the birth of symbols. When looking at a pacific symbol, a swastika or a red five-pointed star, any person reads a huge layer of information, which otherwise would have to be covered in several volumes. However, of course, symbols existed before. Let's say a crucifix, a crescent or a mogendovid (Magen David). Or coats of arms of cities, clans and royal houses. The only difference is that it was a rather limited set of religious and secular symbols.