Day two of the trek made this fact especially evident, as we descended from the snow-capped pass’s puna grassland into a humid Amazonian rain forest teeming with mosquitoes, all within a matter of hours. After a brief pause for lunch, we struck off on a side trip to the Humantay Glacier. The scrubby, striated slopes leading up to it were far steeper than they appeared. When I paused to catch my breath—which was often—I could count my pulse without placing a finger on my wrist. An hour and a half later, we reached the lake at the base of the glacier, its quiet surface a pale jade. Water traced silvery veins across the sheer cliff face; ice frequently broke away, filling the air with the sound of thunder and the smoky whiteness of an avalanche; countless apacheta lined the shore. We were the only people there. As if by an unspoken agreement, members of the group scattered, each pulled in a different direction by the experience. I found a seat on a secluded boulder as tears filled my eyes. No matter the final destination of a trip—even one as magnificent as Machu Picchu and Choquequirao Trek —it is the wonders that unfold along the way that bring us the deepest joy.