The largest waterfalls in South America, and one of the great sights of the world, are buried deep in the continent, at Iguassu (which means "Big Water" in the local Tupi language). The river Iguazu falls 270 ft over a basalt cliff into a canyon which then drains into the nearby Parana river and flows out, eventually, to the South Atlantic. The total surface area of falling water at 1.3 million sq ft is 2nd only to the Vitoria Falls in Africa (1.8 million sq ft), but here it is divided into 275 separate cascades creating a vista of waterfalls.
The Falls lie on the border between Brazil and Argentina, and both have excellent viewing points for tourists. Both are impressive, but it has to be said that the most spectacular is the Devils Throat, on the Argentine side.
The Brazilian side uses buses to transport you around the site. One option here is the Macuco Safari, which takes you by speed boat along the canyon and then directly under a waterfall (you will get wet!). Access on the Argentine side is via the "Rainforest Ecological Train" which trundles though 5 miles of the National Park to a little station where one exits and walks about a mile on a raised footpath to the falls. The train incidentally was built in Ross on Wye in England, and transports about 900,000 passengers a year though the forest.
Iguassu is surrounded by national parks on both the Brazilian and Argentine sides, with a total area of 868 sq miles. This huge area of forest and rivers, recognised as a UNESCO World Heritage Site, contains rare giant otters, giant ant eaters, jaguars, tapirs, parrots and toucans. There are over 500 species of butterflies, and 5 species of swallows whose flying displays chasing insects through the spray add an extra element to the splendour. A truly spectacular place.