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The Treaty of Valparaiso was an agreement between Chile and Bolivia that ended the War of the Pacific. Signed on April 4, 1884, the third treaty of the war forced Bolivia to give Antofagasta to Chile.
References
Tucker, Spencer (2010). A Global Chronology of Conflict. ABC-CLIO, LLC. p. 1482.
Calvert, Peter (1994). The International Politics of Latin America. Manchester University Press. p. 80.