European Commission President Jean-Claude Juncker (C) arrives for the opening ceremony of the Karl Marx exhibition, at the Basilica of Constantine in Trier, Germany, on May 4, 2018. European Commission President Jean-Claude Juncker said Friday that Karl Marx was a forward-looking philosopher and his works changed the world, as Marx's hometown Trier is marking the thinker's 200th birthday. (Xinhua/Shan Yuqi)