There is a deafening roar, a wall of white blinding mist and then everything is wet.
A puddle of water laps in my seat and an earthy bitterness pricks my tongue but I am in such raptures I can't close my mouth.
By the time the voyage is over, my knickers will need to be wrung out and my hair will be dripping but I don't care.
On the bus to Iguazu Falls, an old Argentine man described his country's most famous landmark thus: "Standing at the waterfall you feel God, God is flowing through the water."
I don't know about God, but I can certainly feel the almighty force of Mother Nature as I am buffeted by a tsunami of water on a speed boat that is little more than a rubber dinghy.
To explore South America's most renowned cataracts, I have joined an adventure safari to the base of the waterfall.
Boarding downstream on the Argentina side of the Iguazu River, all was quiet and serene. The river was fast flowing but there was no sign of the tumult ahead.
Soon we were ski jumping over frappuccino rapids, creamy torrents burst from the river bank and an impenetrable mountain of crashing water lay dead ahead. The boat edged tantalisingly close to where the falls explode and then there was a tremendous assault on the senses.
First, the thundering noise, the blinding spray and then the drenching backwash of water. And it's a lot of water.
More than an Olympic-sized swimming pool of the stuff crashes down the falls every two seconds and that's on an average day.
Today, the river is so full boat crossings to San Martin Island have been cancelled and thrill seekers risking the walk to the boat launch look in danger of being blasted off the path.
Much of the riverbank has been swallowed by opaque cascades and the grey sky, falls and mist have melded into an atomic cloud of vapour. It is an awesome spectacle.
Iguazu Falls, meaning "great waters", are located in the northeast corner of Argentina and slice through the Brazilian border. They were formed 200,000 years ago by a geological fault that opened up the earth, sending the Iguazu River tumbling 80m over a half-moon crater of sandstone and basalt.
Iguazu has been amazing crowds for years but the attraction is also a feat of man-made ingenuity. The highlight is at the crest of the falls, known as the Devil's Throat, where a perilous catwalk is anchored into the raging current. Here, sightseers stand suspended centimetres above the lip of the biggest waterfall and can peer into the frothing abyss.
A network of other viewing platforms snake across the river and islands, taking inmost of the 200 cascades that make up the upper and lower falls of the Iguazu complex.
It's a full-day adventure and that's just on the Argentina side. On the Brazilian side, the viewing areas are a little further from the action but afford an incredible panorama of the whole tiered display.
And there are still plenty of opportunities to get wet. When I cross the border, the main viewing tower is like a lighthouse being pummelled by an inverted ocean of water. There is a runway to the centre of the river but, today, the water splutters and sheets horizontally over the rails, like an industrial bio-hazard shower.
The traders selling plastic ponchos are doing a roaring trade but man-made fibres are little contest against the fury of nature. And who needs them anyway?
When you come this far, it's hard to resist diving in head first, metaphorically speaking, and soaking up the experience.
When your shoes are squelching and your entrance ticket is sodden in your pocket, you know you have felt the power of Iguazu.
Just be sure to bring a change of clothes. And don't forget a spare pair of knickers.
Getting there: LAN Airlines operates six days a week from Auckland to Santiago de Chile, with onward connections to Iguazu Falls.
Getting around: World Journeys has a 12-days, 9-nights package starting from $5995 per person (share twin), including return air fares from Auckland, which takes in Iguazu as well as Santiago, Vina del Mar and Valparaiso in Chile; Buenos Aires and a tango show; three nights in Rio with a typical churrascaria dinner, samba show, Corcovado Mountain and the Statue of Christ.
Further information: See iguazuargentina.com.