Iguazú National Park

Iguazú National Park protects the Argentine bank of the falls system on the Iguazú River, shortly before it joins the Paraná. The drop occurs where the river crosses a series of basalt flows from the great Paraná-Etendeka volcanic outpouring: the basalts, fractured and of uneven hardness, have retreated irregularly and produced a stepped front with more than two hundred separate falls, dominated by the Devil's Throat, a horseshoe where the greatest volume of water is concentrated. The surroundings are Paranaense forest, or interior Atlantic Forest, one of the most threatened ecosystems in South America, of which only a fraction of its original extent survives; the block formed by this park and the Brazilian Iguaçu is one of its last continuous stretches of any significant size. It holds jaguar, tapir, coati, toucans and the great dusky swift, which nests behind the curtains of water. Argentina and Brazil protected it separately in 1934 and 1939, and both are inscribed as World Heritage Sites.