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The Iguazu River, which cascades spectacularly over basalt cliffs, divides Misiones, Argentina's northeasternmost province, from Brazil.

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In remote Misiones, human settlement is scant, limited to a few lonely pioneers who eke out a living by planting tea, bananas, and tobacco.

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About a million people live in Misiones, one the smallest of Argentina's 23 provinces.

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Misiones gets its name from the many missions, such as San Ignacio Mina, established by the Jesuits during colonial times.

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Originally home to Guarani tribes, Misiones is now the turf of gauchos, or Argentine cowboys.

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Settlers cleared much of the province's original forest, but 4,250 square miles are still preserved in a string of wildlife reserves.

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Lianas fall from the canopy and epiphytes and philodendrons coat every exposed trunk and branch in what's left of the old-growth jungle.

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It's common to see blond-haired, blue-eyed villagers throughout Misiones, thanks to a 20th century migration of Poles, Germans, and Ukrainians.

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This particular South American rattlesnake is kept as a pet by a Misiones farmer, Juan Podkowa.

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At Misiones' Don Enrique Lodge, each cabin opens to a private, waterside veranda.

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Tacuapa Lodge's battered Isuzu takes visitors crashing through dense brush and across rivers and arroyos.

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Guide Fidel Ramirez used a machete to clear the path.

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Ramirez scanned the dense boughs of tropical cedar, earpod, and rosewood trees in search of birds.

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The black-throated trogon is one of the Misiones jungle's shyest birds.

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This black-throated trogon was summoned from the forest's densest recesses by Fidel Ramirez.

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The black-breasted plovercrest is a spectacular hummingbird topped with a purple crown.

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In the jungle, the band-tailed manakin is often heard but rarely seen.

Colin Barraclough for the Boston Globe

A white woodpecker.