evidence: The Isla Suárez (Bolivia) or Ilha de Guajará-Mirim (Brazil) is one of the world's many disputed territories. The island lies in the Rio Mamoré, which defines part of the boundary between the Bolivian department of Beni and the Brazilian state of Rondônia. Map of Isla Su%C3%A1rez, Bolivia Isla Suárez Wikipedia(Text) CC BY-SA