I’d seen waterfalls before, but never like this. I was sliding down a wire some 50 feet (15 m) in the air, sailing through the treetops at 30 miles an hour (48 km/h). Somewhere off to the left of me ...

Steam rises from the slate-lined pools thick as smoke, veiling the blood-red walkway in front of me, muffling the voices of those already soaking in the hot springs of Termas Geométricas near Pucón, ...