On December 6 2013, the United Nations General Assembly adopted a resolution (A/RES/68/239) designating October 31 as World City Day. This was a result of the efforts made by the Chinese government, the BIE and the related UN organizations to promote sustainable world city development. Shangai World Expo 2010, with the theme Better City, Better Life, was a major event in terms of public participation and innovation in the fields of energy. The issues under discussion were related to energy-saving, reduction of CO2 emission and eco-development.

World Expos are global forums that are put into practice each five years and that expound different interests for governments and countries. They give concrete responses to social and technological problems in different areas of expertise and aim for a long-term legacy. The legacy of recent and current Expos translates into sustainability and sustainability translates into the positions and long-term strategy of the world's cities.

There are two categories of international exhibitions. The BIE makes the difference between World Expos and International Expos. They differ principally in the size of the Expo site, the duration of the event and the scope of the theme. In terms of benefits, World Expos are an attractive way of making business or attracting visitors. Nevertheless, nations can expect more than just an economic impact. Shanghai 2010 is a good example of improved international self-confidence and soft diplomacy.

The theme should reflect the essential aspects of the identity, history and culture of the organising country while addressing subjects of international relevance. It should enable the development of different topics to launch and sustain a broad programme of public dialogue. It should stimulate an interest for exchange and co-operation from participants. Last but not least, it should appeal to both the rationality and emotions of their citizens who must be able to relate the theme to their daily lives and their most vital concerns.

Expo 2010 represented the crystallization of the commitment and dedication of the Chinese government, of its people and of the international community in order to achieve this important event. What started out as a "vision" and a "dream" of a small group of individuals who understood the transformative value of an Expo for the city of Shanghai and for China, the Expo Shanghai project has since blossomed into a nationwide mobilization of the largest scale, attracting the attention of the entire international community.

The mission of the Bureau International des Expositions (BIE) is to facilitate the connection between the different actors of the Expo in order to foment multilateral public diplomacy. "Expos can be sources of inspiration and support for large public communication campaign of different types". For governments and the international community, Expos offer a unique platform for multilateral public diplomacy: they are platforms to educate the public and vehicles to promote national identity, away from local political debates.