Town twinning is characterized by solidarity and civic fraternization. These goals date back to the years of the post-war period, when  town twinning was the vanguard of a nation-state rapprochement, and were seen as small bulwarks against a renewed outbreak of hostilities. The efforts of such partnerships were therefore directed towards cultural exchange and the knowledge of other societies and ways of life. Cultural relations have developed into ever closer and more diverse forms of cooperation, as Zurich's partnerships with Kunming and San Francisco impressively demonstrate.