At first glimpse, the Rio Irigoyen was nothing like I had imagined. This wasn't the barren, austral, treeless landscape found at the Rio Grande. It was a smaller, more inviting, meandering waterway, nestled in a green hollow, and lined by towering lenga tree forests. It flowed like a gentle mirage under a whispy layer of fog, like a setting from Lord of the Rings, or better yet, King Kong. Despite its benign and inviting fa¿¿ade, you immediately got a sense that this was a truly wild river, and giant beasts lurked below its surface.