Iguazu Falls: The Thundering Curtain on the Brazil-Argentina Border

The Iguazu Falls straddle the border between Brazil and Argentina in a horseshoe of 275 individual cataracts stretching nearly three kilometres across the Iguazu River. The falls were formed when a volcanic eruption created a fault in the basalt plateau, and the river — which drains a basin the size of the United Kingdom — drops between 60 and 82 metres over the edge in a continuous roar of white water and spray. Eleanor Roosevelt, on seeing the falls for the first time, reportedly said 'Poor Niagara' — a comparison that is entirely apt, since Iguazu is four times wider and significantly taller.

The Devil's Throat — Garganta del Diablo in Spanish, Garganta do Diabo in Portuguese — is the most powerful section of the falls, a U-shaped chasm 150 metres wide and 700 metres long into which fourteen of the largest cataracts plunge simultaneously. Standing on the walkway at the lip of the Devil's Throat, with the spray rising 30 metres above the falls and the roar making conversation impossible, is one of the most physically overwhelming experiences in nature. The walkway is accessible from the Argentine side and requires a train journey through the subtropical forest to reach it.

The falls can be experienced from both sides of the border, and the two perspectives are complementary rather than redundant. The Brazilian side offers the panoramic view — a single walkway that runs along the canyon rim and provides the classic wide-angle vista of the entire horseshoe. The Argentine side offers immersion — a network of trails and walkways that takes you to the base of individual falls, onto islands in the middle of the river, and to the lip of the Devil's Throat. Spending a day on each side is the ideal approach.

The Iguazu National Parks on both sides of the border protect the subtropical Atlantic Forest that surrounds the falls — one of the most biodiverse forest ecosystems in South America, and one of the most threatened. The forest is home to jaguars, tapirs, giant anteaters, and over 400 species of bird, including the great dusky swift, which nests behind the falls themselves and can be seen flying through the curtains of water. Coatis — raccoon-like mammals with long, flexible snouts — are ubiquitous around the visitor areas and have learned to steal food from tourists with impressive boldness.

The boat tours that take visitors directly beneath the falls are the most visceral way to experience Iguazu — the boats approach the base of the cataracts until the passengers are completely drenched, the noise is deafening, and the scale of the water above becomes truly apparent. The tours operate from both sides of the border and last about 15 minutes; bringing a waterproof bag for cameras and phones is essential, as the spray begins well before the boat reaches the falls themselves.

The town of Puerto Iguazú on the Argentine side and Foz do Iguaçu on the Brazilian side are the main bases for visiting the falls. Puerto Iguazú is the smaller and more pleasant of the two, with a good selection of restaurants serving Argentine grilled meats and a relaxed atmosphere. The Itaipu Dam, 20 kilometres north of Foz do Iguaçu, is the world's second-largest hydroelectric dam and generates 17 percent of Brazil's electricity — a remarkable piece of engineering that offers a very different perspective on the power of the Iguazu River.

The best time to visit is from March to May, when the water levels are highest after the rainy season and the falls are at their most powerful. The dry season from June to August reduces the flow significantly but makes the walkways less slippery and the forest easier to explore. The falls are open year-round, and the subtropical climate means that even the winter months are warm enough for comfortable visiting. Arriving early in the morning, before the tour groups from Buenos Aires and São Paulo, gives you the best chance of experiencing the falls without crowds.