As Europe prepares to mark the centenary of the start of World War I, the DOX Centre for Contemporary Art in the Czech capital, Prague, is hosting an exhibition of political propaganda from the first modern war until today. The exhibit, titled "The Poster in the Clash of Ideologies 1914-2014," tracks poster art and its political messages from the world wars through the Cold War, the "war on terror," and the social and economic crises of recent years. (Photos courtesy of Ne boltai! Collection, Moravian Gallery in Brno, Interference Archive, authors and DOX Centre for Contemporary Art.)