I had meant to sign up for five days, tops. Then I saw the map of the river. It covered the entire wall of the tour agency’s office in Lagunas, a village gateway for river journeys into the Peruvian Amazon. I had arrived during the rainy season in 2015 and the jungle was flooded. Five days paddling downstream in a dugout canoe would take me barely halfway up the wall.

My mind began to race ahead. I stared intently at the bright blue rivulet, followed its curves upwards to where it pooled into a lake, then dropped sharply off the edge of the wall. “What’s there?” I asked.

“Lago Pastococha,” the agent said, with a whispery reverence that made an impression on me. “It’s pure wilderness there.”

• Tags: Emily Ding, Malaysia