MILLIONS of tons of water thundered towards me, but only a curtain of spray 50 metres high gently soaked my forehead, cooling in the tropical heat. I tried not to think about the thin ribbon of concrete under my feet, which had taken me into the very jaws of the Devil's Throat, 14 separate falls, deafening in their fury. A similar concrete causeway on the Argentinian side of the Iguacu Falls had been swept away mercilessly by these raging waters. Fortunately it happened during darkness, and no one was killed. To see the Iguacu Falls from the grounds of my hotel had been one thing; to be in the midst of these 275 falls, plunging 90 metres from the Iguacu river, was something else. The Devil's roar leaves you feeling totally helpless. The falls, at the borders of Brazil, Argentina and Paraguay, will be remembered by many as the setting for part of the feature film, The Mission. Three kilometres wide, they are regarded by many as the greatest natural wonder in Brazil, and that is quite an accolade when one considers the diversity in this the fifth largest country in the world. If you are wealthy enough, you can stay in the magnificent colonial Hotel Das Catar Atas, overlooking the falls in splendid solitude in the forested national park on the Brazil side. Cross the border into Argentina, and the Hotel Internacional Iguazu, modern and sleek, supplies an even better setting, with panoramic views. The Das Catar Atas, while offering other-worldly charm and opulence, also has some minor drawbacks associated with its age - rattling sash windows. I had tossed and turned for an hour before grabbing a newspaper in frustration to wedge under the window. There was no need. A proper wooden wedge came with the room, with a notice telling guests to use it to stop the rattling. They say there is a pot of gold at the end of the rainbow, and of course normally one cannot find the end. But at the Iguacu Falls there are permanent rainbows, some of them only 25 metres or so from end to end. No person would dare defy these waters. Amazingly, a small bird, the swift, does so with impunity. Hundreds of them fly through the sheets of spray, catching insects, and then dart through the seemingly impenetrable walls of water, clinging to the sheer, slippery rock faces behind. Here they sleep, safe from predators, the Devil's Throat proving to be their guardian. The Argentine side of the Iguacu Falls may only be a stone's throw away, but to get there you must drive for around 40 kilometres. My guide scampered off with my passport and within 30 minutes had re-appeared with a one-day border pass. Crossing the bridge over the Iguacu River that connects Brazil and Argentina, you enter a national park with a difference, a national park with a military base. At its entrance, a statue of a Marine hunches aggressively, sub-machine gun levelled at passing civilian traffic. And the Argentinians have not forgotten their war with Britain. A sign reads in Spanish: The Falklands belong to Argentina. Argentina's economic woes of the past few years are also evident at each side of the road leading to the falls. Three hotels are half-built and abandoned, surrounded by barbed wire fencing. Traders had started to build the hotels, but when the economy collapsed there was no money to complete them. Argentinians began crossing over to Brazil to buy food. But nearby Paraguay has no such problems. It has become a duty-free paradise, the economy inspired by Chinese immigrants, many from Hong Kong. Next year Brazil, Argentina, Uruguay and Paraguay will form a South American common market, so those hotels in Argentina may eventually be completed. My guide tells me Argentina learnt from its humiliating defeat in the Falklands that it could no longer go it alone without the rest of South America, and ties with Brazil have strengthened remarkably. The journey to the Argentine side is not to be missed, however, in spite of the economic woes and the military base. In the National Park, pathways lead to the very lip of some of the falls, and you can watch the water plunging right beneath your feet. Don't go if you suffer from vertigo. The botanical wonderland around the falls has been well preserved by the Argentinians, and many of the species of flora are labelled. There are also some unusual souvenirs to be bought. Look out for vendors of instant art. They grab a plain white plate, a palette of paints and cotton wool balls. Hey Presto! In two minutes the Iguacu Falls tumble across the tableware. Monkeys also scurry out of the forest, unafraid. They prefer a diet of coke and biscuits to the jungle fare. And down here the military presence is low-key, the park staff and souvenir stall-holders friendly and polite. A former holy burial site for local jungle tribes, the Iguacu Falls were declared a world heritage site by UNESCO in 1986. It is a tribute they richly deserve. Varig Airlines fly twice-weekly from Hong Kong to Sao Paulo and Rio. They can arrange package tours to Brazil which include a visit to the falls. On the Road will appear tomorrow.