I was in Berlin on the night of the United States presidential election, waiting for the Falling Walls conference to begin on 9 November. The bruising 2016 presidential campaign revealed societal fragmentation across the nation. Being in Berlin to absorb the election news had some unique resonances. Here, history has shown that there can be grave dangers in division and benefits of unification. Yet countries everywhere are showing signs of deep polarization. We must understand more fully these divisions. Communities at all levels and across sectors must work hard on drawing citizenry, and the world, together. The scientific community must recognize its important role in helping to break down barriers and find solutions that will build better lives for everyone.