But more nature lovers are now exploring the toucan- and butterfly-filled Green Corridor that has long been overshadowed by the falls.

WSJ: Bird Watching in Misiones Province, Argentina

Half-asleep, I shuffled to the canopy-level observation deck of my rustic wooden cabin, grabbing binoculars and Tito Narosky's "Birds of Argentina and Uruguay" just as a flurry of yellow plumage transformed into what locals term the "banana toucan, " a rare and striking saffron toucanet.

WSJ: Bird Watching in Misiones Province, Argentina

For private hire and sleeping twelve, head out cayman tracking by motorized canoe, swim with pink river dolphins - the boto rosa -- or try a spot of piranha fishing before taking to the skies in a Cessna Amphibian to experience the jungle like a toucan.

FORBES: First Class Amazon River Cruise