“I knew we were definitely entering the world of the rain forest, the lush jungle of mystery that only deepened and became more dangerous with each passing second. The river narrowed, and the air grew still with the dark pungent scents of the deep rain forest. I had recognized the signs. Soon, the river would be impossible to navigate. I had said to my partner then. They would be forced to abandon the boats and tramp through the forest on foot. Unlike many places in the rain forest where it was easy to walk because very little could live on the forest floor without too much light, this area was...