At dawn on June 6, more than 30 years after Lynn was chasing tortoises at the top of Alcedo, our boat anchored near the volcano’s base in Urbina Bay. By 8 a.m., I was fully breakfasted and eager to begin the scheduled 2-mile hike, on which we were likely to see giant tortoises and land iguanas.

My mood dampened after disembarking on the beach. Even at this early hour, and even doused ear-to-toe with 100-SPF sunscreen, I felt an unrelenting solar assault. (Turns out it’s hard to concentrate on nature’s glories while obsessively imagining your skin cells morphing into irregularly shaped cancerous moles.) The beach was narrow and surrounded by foreboding gray rocks. Maybe this, I thought, is what Darwin