1,330km (825 miles) NE of Buenos Aires

A dazzling panorama of cascades whose power overwhelms the sounds of the surrounding jungle, Las Cataratas del Iguazú (Iguazú Falls) refers to the spectacular canyon of waterfalls fed by the Río Iguazú. Declared a World Heritage Site by UNESCO in 1984, these 275 waterfalls were shaped by 120 million years of geological upheaval, forming one of earth's most unforgettable sights. Iguazú Falls are shared by Argentina and Brazil, and are easily accessible from nearby Paraguay as well. One million visitors a year means the park has become somewhat overdeveloped, with too many restaurants and a theme park-style railway. However, the falls are too huge and magnificent to be encroached upon completely by humans, and the excellent walking circuits on both the Argentine and Brazilian sides allow visitors to peek over the tops and almost touch the torrent. Most visitors stay in the towns of Puerto Iguazú, in Argentina, or Foz do Iguaçu, in Brazil, or in some well-appointed hotels on the road to the park.

Worth exploring is the park's subtropical jungle. Here, cupay trees (South American hardwoods) tower over the various layers of life that compete for light; and the national park is known to contain 200 species of trees, 448 species of birds, 71 species of mammals, 36 species of reptiles, 20 species of amphibians, and more than 250 species of butterflies. Iguazú's climate also provides for the flowering of plants year-round, lending brilliant color to the forest. Because spray from the waterfall keeps humidity levels over 75%, there's a tremendous growth of epiphytes, or plants that grow on other plants without taking nutrients from their hosts.

You can visit the waterfalls on your own, but you will most certainly need a tour operator to explore the jungle. Allow at least 1 full day to explore the waterfalls on the Argentine side, another to visit the Brazilian side, and perhaps half a day for a jungle tour. Many visitors base themselves in the sedate town of Puerto Iguazú, 18km (11 miles) from the park. Though hardly the most memorable place, Puerto Iguazú has a subdued charm, pretty vegetation, and friendly people, and it's not yet ruined by the tourist trade. Accommodations options are improving all the time. If you want something more vibrant, go to the Brazilian town of Foz do Iguaçu, on the other side.