European Commission President Jean-Claude Juncker (L) and governor of Rhineland-Palatinate Malu Dreyer (C) pose for photos prior to 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)