El Impenetrable National Park is as daunting a landscape as the name suggests. Stands of quebracho—often called the hardest wood in the world—dominate the park’s uplands; elsewhere, thick knots of locust trees, palms, and even cacti create a dense patchwork of forest. The Teuco River winds through this corner of northern Argentina’s Chaco Province like a muddy yellow serpent, flooding seasonally and making much of the area impassable for weeks at a time. But the river also sustains resident flora and fauna during the dry season, which lasts most of…
