Alain Berset (L), president of the Swiss Confederation, shakes hands with Klaus Schwab, founder and chief executive of the World Economic Forum (WEF), during the opening ceremony of the WEP annual meeting at Congress Center in Davos, Switzerland, Jan. 23, 2018. Heads of state called for 2018 to be the year of collaboration and multilateralism to address major global challenges like climate change, terrorism and protectionism, as the World Economic Forum (WEP) opened in Davos, Switzerland, on Tuesday. (Xinhua/Xu Jinquan)