Belgium's King Philippe (second left) and Queen Mathilde (right) enjoy a walk with Chinese President Xi Jinping (second right) and his wife Peng Liyuan at Laeken Royal Palace in Brussels on Sunday. Belgium is the last leg of Xi's four-nation Europe trip, which has already taken him to the Netherlands, France and Germany. He also attended the third Nuclear Security Summit in The Hague. Xi is the first Chinese leader to visit the European Union's headquarters since Brussels established ties with Beijing four decades ago. Yves Herman / Reuters