FROM the air, Iguassu Falls looks like something out of a science fiction movie - a fierce crack in the earth with thousands of megalitres of water barrelling into an abyss.
Now and again, furious plumes of mist shoot hundreds of metres into the air, seeming to amplify the roar from a dead-end corridor enveloped by a curtain of water: the Devil's Throat.
At the height of the wet season, the equivalent of more than 80 Olympic pools crash over the falls every minute.
It is awesome, not least because its cloud and thunder are camouflaged by 185,000ha of South American rainforest jungle.
Iguassu Falls, when the river is at just the right level, can have as many as 276 separate waterfalls, sprouting from more than 2.5km of cliff faces.
Spanish explorer Alvar Nunez Cabeza de Vaca was the first European to report seeing it. He was there in 1542, but it was more than 60 years before Europeans returned.
The Iguassu River now marks part of the border between Brazil and Argentina.
The countries eye each across the falls kerfuffle, without a hint of tension.
Less than 10km downriver, though, it is a different story. Ruthlessly efficient customs officers from both countries vigorously search cars, mini-vans and buses. Backpackers, in a long, frayed line, are of particular interest.
"We are very close to the Paraguay border here, too," said Douglas Thiago, a 20-year-old engineering student and our guide. "Its border is open: no customs checks."
Are they worried about drugs?
A nod ... "and guns".
The controls, though tough, work.
Thousands of visitors - from squealing, soaked primary school children on excursions to besotted international travellers - take to the parks every day.
Brazil and Argentina each has a national park gathered up around the falls. The larger is the Argentinian.
Each park has something a little different to offer.
Brazil's has an easy walk that can take less than a couple of hours around the bottom of the falls. It has paths and walkways out over the river that are guaranteed to get you close to one of nature's most spectacular shows.
Helicopter rides over the falls fly from just outside the park gate.
From the Argentinian side, you can take IRB runs under the falls, jump on a "trail bus" through the jungle, or hop on a 15-minute train ride to the top of the falls.
From the top, there is an impressive, kilometre-long walkway stretching across the falls to the Devil's Throat. It is quite an engineering feat, perched at the edge of such power.
Both parks are alive with animals.
And you could almost forget that the entire area is national parks, if it were not for "visitors".
At the Orient-Express's Hotel das Cataratas, few experiences feel more like an exotic holiday than sitting by the pool, daiquiri in hand after a day at the falls, watching toucans try to steal eggs from the nests of squawking black-and-red weaver birds. A giant guinea pig - a capybara - forages in a courtyard just outside one of the hotel wings.
Staff chase away a couple of scavenging coatimundi (long-nosed relatives of the raccoon) that come in hunting for breakfast, and a metre-long iguana suns itself on the hotel's front lawn.
Parque de Aves, a bird park just near the helipad, has thousands of South American birds, from hummingbirds to condors in cages that cover up to half-a-hectare.
The birds have been drawn from throughout the continent, and the continent has more than 70% of the world's bird species. It is well worth putting aside half a day to see.
Iguassu Falls, presently vying to become one of the world's seven natural wonders in an online vote, is as astounding as it is surprising.
The Falls have featured in several movies
The Mission (1986)
Mr Magoo (1997)
Miami Vice (2006)
Indiana Jones And The Kingdom Of The Crystal Skull (2008)
The Falls figures
The falls stretch for about 2.5km on the Iguassu River
Surface water flowing over the falls is double that of Niagara Falls
When translated from the native Indian language, Iguassu roughly translates to "big water"
Tina Lord Roberts, a character from the US soap opera One Life To Live, in a 1987 episode supposedly went over the Iguassu Falls and was killed. In the true tradition of soapies, the character later returned in the series.
It is awesome, not least because its cloud and thunder is camouflaged by 185,000ha of South American rainforest jungle.
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