Iguazu Falls are waterfalls of the Iguazu River located on the border of the Brazilian state of Parana and the Argentine province of Misiones. The falls divide the river into the upper and lower Iguazu.

Taller and far wider than Niagara Falls, twice as wide with 275 cascades spread in a horsehoe shape over nearly two miles of the Iguazu River, Iguazú Falls are the result of a volcanic eruption which left yet another large crack in the earth. During the rainy season of November - March, the rate of flow of water going over the falls may reach 450,000 cubic feet (12,750 cubic m) per second.

The name of the falls comes from the Guarani word for "great water". Legend has it that a god planned to marry a beautiful aborigine named Naipi, who fled with her mortal lover Taroba in a canoe. In rage, the god sliced the river creating the waterfalls, condemning the lovers to an eternal fall. The first European to find the falls was the Spanish Conquistador Alvar Nunez Cabeza de Vaca in 1541, after whom one of the falls in the Argentine side is named. The falls were rediscovered by Boselli at the end of the nineteenth century, and one of the Argentinian falls is named after him.

The waterfall system consists of 275 falls along 2.7 kilometers (1.67 miles) of the Iguazu River. Some of the individual falls are up to 82 meters (269 ft) in height, though the majority are about 64 metres (210 ft). The Garganta del Diablo (Devil's Throat in English; Garganta do Diabo in Portuguese), a U-shaped 82-metre-high, 150-metre-wide and 700-metre-long (490 by 2300 feet) cliff, is the most impressive of all, and marks the border between Argentina and Brazil. Two thirds of the falls are within Argentine territory. About 900 metres of the 2.7-kilometer length does not have water flowing over it. The edge of the basalt cap recedes only 3 mm per year. The water of the lower Iguazu collects in a canyon that drains into the Rio Parana in Argentina, shortly downstream from the Itaipu dam.

The falls are part of a singular practically virgin jungle ecosystem protected by Argentine and Brazilian national parks on either side of the cascades. Two thirds of the falls are on the Argentinian side of the river where you can also tour Iguazú National Park where there are jungle trails and bird hikes. Plan a full day in the park to fully enjoy the wildlife flora and fauna. These parks were designated UNESCO World Heritage Sites in 1984 and 1986, respectively.

It is possible to see the falls and surrounding area in a lightning trip but it is better to plan at least two days. The view from the Brazilian side is the most panoramic and there are helicopter rides out over the falls from Foz do Iguaçu. You may also take boat rides out to the falls. The light is best in the morning for photographs.

Best seen from the Brazilian side is the spectacular Devil's Throat, garganta del diablo, where fourteen falls drop 350 feet with such force that there is always a 100 foot cloud of spray overhead. Watch for the rainbow! For a close up view, walk through the subtropical forest of National Iguaçu Park to the base of Salto Floriano and take the elevator to the top of the falls. or walk out over the falls at Salto Union. From the Argentine side you can take a series of catwalks over the water rushing into Devil's Gorge. Protective rain suits are provided. There are some areas where it is possible to swim in the spray of the cascades. Ask locally for instructions but be aware that you might have a resulting problem with cuticle parasites.

The best times to see Iguazu Falls are in the spring and fall. Summer is intensely tropically hot and humid, and in winter the water level is considerably lower. There are hotels on both sides of the river and many tour agencies provide sightseeing opportunities around the area. Browse through this list of hotels on the Brazilian side of the falls, or these on the Argentine side.