Bolivia and Paraguay have signed an historic agreement bringing to an end a border dispute.
Bolivian President Evo Morales and his Paraguayan counterpart Fernando Lugo met at the residential palace of Argentine president Christina Fernandez de Kirchner to formally restore relations.
At the ceremony both men praised the historical importance of the document.
The dispute between the two countries centred around control of the Gran Chaco region, which was mistakenly thought to be rich in oil, during the 1930s. Backed by Western oil companies around a 100,000 people died in the conflict.
Outside the presidential palace in Buenos Aires a number of Bolivian nationals living in Argentina gathered to witness the event.