The Caingangue people tell of a maiden called Naipi who was promised to the snake god Mboi.
But Naipi had a lover called Taroba and together they escaped in his canoe down the Iguazú River that now divides Brazil and Argentina. The snake god, in his fury, threw himself into the ground and created a vast cataract into which the river cascaded, taking the terrified lovers with it. Today, you can still hear their screams as they plunge for ever in the water rush.
Today, you can also vote for Iguazú Falls as one of the New Seven Wonders of Nature, an international poll that is being organised by Swiss cultural enthusiast, Bernard Weber. There are currently 28 finalists and the results will be published on 11 November. When Weber ran his last poll, to find the New Seven Wonders of the World, the president of Brazil got his people out to elect the statue of Christ the Redeemer. I wouldn't be surprised if the same thing happens with Iguazú. Having said that, Iguazú would get my vote.
I arrived in the middle of a hot, sticky afternoon: humidity 95 per cent. Hotel das Cataratas is the only hotel within the Iguazú National Park and the receptionist advised me to wait until 6pm before going out. It was good advice because the park closes around 5pm, leaving hotel guests with the place to themselves.
I crossed the lawns that descend rapidly to a small paved vantage point from which came what sounded like the deep-throated roar of traffic. I knew my first glimpse of the falls was coming, but I tried not to look until the last moment. I first saw clouds of spray shot through with the rays of the dipping sun, then column after column of white water crashing down from the river's Argentinian side.
There are 275 individual waterfalls making up Iguazú, the largest sequence in the world. They were created 150 million years ago when an earthquake of unbelievable proportions dropped this section of the river valley 80 metres into the earth. The river has not smoothed this drop, just cut back relentlessly, creating two huge bites out of a meander loop in the river. It's a sight that thrills. "Poor Niagara," is what Eleanor Roosevelt is supposed to have said on first catching sight of Iguazú. You half expect to see a dinosaur wander by vacuuming up the lush vegetation.
I saw no dinosaurs, but masses of butterflies of all colours and patterns. To thrive, butterflies need heat, moisture and no pollution. The air purity at Iguazú is borne out by the fact that there are 40 different butterfly species.
As it would be dusk soon, I began walking towards the Devil's Throat, the most impressive single waterfall, which is firmly on the Brazilian side of the border. There is a well-made path leading down to the water's edge. The setting sun was creating golden shafts of light through the mist clouds as I disappeared into a virtual tunnel of canopied trees. The whole scene had an air of unreality.
Then I saw them: first just one, a fawn-coloured creature with a black-striped tail, walking towards me. It was about the size of a large cat with the pointed face of a badger. I expected it to notice me and bolt, but it walked on past and from behind the mass of foliage came others. They made for the rubbish bins and I got the impression that they had been waiting for the humans to leave.
These were coatis and they took me wholly in their stride. I, on the other hand, fumbled with my telephoto lens, shocked to realise that I was in the presence of a creature I had never seen or known of before. I photographed away as I listened to the chirrups they made which were like the squeakers in cheap cuddly toys. A younger coati climbed up the pole supporting two rubbish bins (I later learned that coatis are born in the trees and learn to climb very early). Once on top, he poked his head in and disappeared into a circular hole designed for dropping in cans. It was quite a squeeze but he did it. A crashing, clunking noise commenced as the youngster sorted through the debris for food, and another entered the next trash bin by the same route, creating more noise.
Coatis can find their own food, but in the national park they scavenge off what we leave behind. They are four-legged Wombles in fact. They're also very bright. When metal plates were put on the bins to restrict access, the adults taught the babies how to squeeze in and bring out morsels. I watched, fascinated, as my first coati emerged and set about cleaning himself on the top of the bin. Then he lost balance, fell on to an older coati, and got a furious telling-off in squeaks.
Having taken enough pictures, I continued my solo journey. There were various vantage points along the way, so you could watch the water charge down. Ahead, I caught sight of a couple from the hotel. By the time I had reached the walkway below the Devil's Throat I was glad of their company as the noise, the spray, and the speed of the water would be eerily threatening if you were on your own.
Several years ago, this concrete walkway was built out across a small plateau that breaks the fall of some of the plunges. The spray was intense enough now to resemble rain. At the end of the platform I was in the middle of the Iguazú River, looking down at the tumult and up to the water as it threw itself relentlessly towards me. I was getting soaked, but I was getting good pictures, too. When I'd had enough, I climbed a concrete tower above the walkway and found the road back to the hotel. Part of the delight of Iguazú is that, unlike "poor Niagara", it has hardly been developed. Although there are shops and a restaurant, I had seen neither. Paths aside, I was in the midst of nature.
The road back to the hotel was wide, empty and slightly forbidding. I was wet and weary and just in front of me passed the most vibrantly coloured snake I'd ever seen: black and white with brilliant coral stripes. I only found out later that the coral snake is the most poisonous in Brazil. Boy, I got a lot of nature that night.
The next day I had booked to visit the Falls by boat. My group was mainly from Argentina plus a few Brazilians. The guide kindly repeated everything in English, even though I could feel growing hostility from the other guests for holding up our arrival.
The excursions are in large inflatables that clock up 30mph bouncing their way to the cataract. Once below, there is a short time to take pictures before the pilot takes you through some of the smaller waterfalls. This I genuinely did not need. It was great to be able to look up into the brilliant blue sky and see water cascading down, but I had no wish to get wet. Most people who do this trip seem to come for the Alton Towers element. The water is warm because the river above is wide and flows in a shallow draught over hot rocks, but you still can't see or hear a damn thing. You just get knocked about. I had stuffed my camera in my waterproof but it stopped working until I took out the battery and let everything dry.
I revisited the Falls once more, this time by helicopter. Having already seen lots of photos of Iguazú from the air, this proved less impressive than it should have been. What surprised me most was the view as we approached the national park (the copters have been moved out to minimise disruption to birdlife). From five miles away the forest seemed to be burning. Great white smoke clouds were rising on the horizon but no, this was spray hundreds of feet high rebounding from the impact below.
As we returned we saw rescue speedboats and helicopters rushing to the Argentine side of Iguazú. One of those inflatables had capsized. Later I found out that two tourists had drowned. Iguazú is vast, wild and beautiful but it is also dangerous. Any force of nature needs to be treated with respect, this one more so than most.
How to get there
Adrian Mourby travelled to Brazil with British Airways (0844 493 0787; ba.com), which offers return flights to Rio de Janeiro from £708. He stayed at the Hotel das Cataratas (0845 077 2222; hoteldascataratas.com), which has double rooms from $375 (£231) a night, including breakfast. Iguazu Falls are about 700 miles/22 hours by road from Rio; daily flights take two hours.
New7Wonders of Nature (new7wonders.com).