UNASUR, or the Union of South American Nations (Unión de Naciones Suramericanas), was formed at the Third South American Summit on 8 December 2004 in Cusco and Ayacuchu, Peru. The Cusco Declaration was a statement of intent which integrated the two existing free trade blocs (MERCOSUR and CAN), while allowing for their continued autonomy. The Constitutive Treaty of the Union of South American Nations was signed on May 23, 2008 during the Third Summit of Heads of State and Government held in Brasília, Brazil.
With the expressed goal to minimize bureaucracy, UNASUR has not yet established its own institutional structure, instead incorporating existing structures of MERCOSUR and CAN. In the future, however, member states of UNASUR aim to follow the European Union by instituting a common currency and passport.
UNASUR is directed by the South American Parliament located in Cochabamba, Bolivia. Its headquarters are in Quito, Ecuador, and its financial centre, the Bank of the South (modelled on the World Bank), is located in Caracas, Venezuela. As of May 2009, UNASUR contained twelve nation states: Bolivia, Colombia, Ecuador and Peru (also members of CAN); Argentina, Brazil, Paraguay, Uruguay and Venezuela (also members of MERCOSUR); and Guyana, Surinam and Chile.