The Iguazú National Park is a national park of Argentina, located in the Iguazú Department, in the north of the province of Misiones, Argentine Mesopotamia. It has an area of 550 km2 (212 sq mi). The park was created in 1934 and it contains one of the greatest natural beauties of Argentina, the Iguazu Falls, surrounded by the subtropical jungle. Across the Iguazu River lies its Brazilian counterpart (Iguaçu National Park). Both sites were declared World Heritage Sites by UNESCO, in 1984 and 1986. – Wikipedia
Cataratas del Iguazú are waterfalls of the Iguazu River located on the border of the Brazilian state of Paraná and the Argentine province of Misiones. The falls divide the river into the upper and lower Iguazu. The Iguazu River starts at the city of Curitiba and runs for the most part of the course entirely in brazilian territory, and in a little part at the end bordering Brazil and Argentina. – Wikipedia
See photos from the Brazil side.