AS we float down the Rio Parana, the only sound we hear is the lapping of waves against the side of the Zodiac. Our guide Kilian has suddenly cut the engine to let us drift and fully appreciate the peacefulness of Argentina's Tigre Delta.
Even petrol stations, schools and hospitals are accessible only by boat in populated areas of the Tigre Delta. Picture: Dan Cooper
We are surrounded by a lush green wall of rainforest and immersed in the soft perfume of subtropical flowering trees.
The Tigre Delta is the ideal place to briefly unwind. Its maze of channels and lush islands provides a tranquil oasis just 20km to the northwest of the tango nightclubs and racing black-and-yellow taxis of Buenos Aires.
Removing his shirt, Kilian slips over the side of the Zodiac and tows it through the water to extend our silent commune with nature. He invites us to join him in the cool river, but we haven't brought our bathing suits so we sit back and relax in the sunshine, happy to let him do the work.
We take deep breaths of the pure air to cleanse our lungs. Occasionally a bird calls and we begin to forget about the capital's heat, noise and pollution. Kilian promises us "the air in the delta is so full of oxygen that you will sleep very well tonight back in the city". All transportation in the delta is by boat; close to 4000 people inhabit the first section, which is made up of traditional houses on stilts and summer cottages for wealthy Buenos Aires residents.
We slowly cruise through the populated part of the delta past these quaint holiday homes, their gardens dotted with bright, blue hydrangeas. Weeping willows stretch down to the cool water; as we pass, people wave from the restaurants and small resorts that line the banks. Even petrol stations, schools and hospitals are accessible only by boat. Children are picked up for their classes in long launches and residents are provided with medical and dental services on a floating hospital. Large grocery boats and water taxis also ply the waterways. We see more active visitors in rented kayaks and canoes and pass a school for wake-boarders.
As we leave the houses behind, the delta opens up into the wide river and just beyond this the dense rainforest closes in. Kilian tells us these waterways trace back more than 1000km into Brazil's Amazon rainforest.
Most animals and snakes have been hunted out here. The jaguars that gave the delta its name of Tigre roamed freely, but they're long gone, as are most of the red deer and wild capybara (a large rodent the size of a hog).
But here on the quiet side tributaries north of the Rio Parana we are completely alone to glide along the many streams and tributaries.
I marvel at how Kilian manages to find his way through the confusing labyrinth of rivers and islands without getting lost. The delta covers 14,000sqkm and the 886sqkm north of the Rio Parana has been declared a protected UNESCO biosphere reserve because of its unique environment. Hunting or logging are no longer allowed.
We finally stop for lunch at a small cabin on a secluded stream and are greeted by Lulu, the owner's pet "otter", which rolls over on its back to have its belly stroked, just like a dog. The otter is actually a nutria, or river rat, similar to a muskrat but a distinct species prized for its fur. Kilian reassures us, however, that they aren't about to skin Lulu. "She's part of the family."
Our home-cooked lunch includes a delicious bife de chorizo (sirloin steak), baked sweet potato, salad, a nice bottle of Argentinian malbec and, for dessert, a pancake with sweet caramel.
The highlight of the tour, however, is yet to come. After lunch, we make an extended trip out to the mouth of the delta where the Rio Parana and the Rio de la Plata meet and spill towards the distant Atlantic Ocean.
As we leave the narrow rainforest streams and slip into the wider river, the sides are lined with several dozen sailboats and large cabin cruisers, the floating retreat of some of the wealthy from Buenos Aires.
Kilian tells us that on weekends there can be a hundred times that many clogging the river. We follow the channel markers into the middle of the Rio de la Plata, dodging some of the larger boats, then stop just to the side of the 15m-deep dredged boat channel.
Kilian cuts the engine again and once more invites us to join him in the water.
We think he means to take another swim, but when he jumps overboard he's standing in 15cm of water, only a few feet away from the 15m drop-off. We cautiously join him in the lukewarm shallows and wiggle our toes on the smooth, sandy bottom. It's as if we're walking on water.
Kilian explains that we could walk from here all the way to Uruguay, even though, at this point, the delta is more than 60km across, the widest in the world.
Every year, 200,000 tonnes of silt from the upper reaches of the rivers in Argentina, Paraguay and Uruguay wash down and are deposited in the delta, creating new islands and sandbars.
Only constant dredging keeps the boat channels open.
In the distance, we can see the skyline of Buenos Aires. Even closer, the sky is dotted with the brightly coloured sails of 50 or more parasailers and surfboarders from marinas in San Isidro and Tigre.
We reluctantly board the Zodiac for the return trip to Tigre and the train back to the chaos of Buenos Aires.