As the powerful Colorado River churned beneath me, as it has for centuries, and the relentless sun peaked over the top of the North Rim, I could not help but feel astounded. I was in a timeless place: a place disconnected from the society I had left behind miles ago. Down here, in the lowest section of the Grand Canyon, it was just me, my friends, and the heat. Always the heat. We had started our journey, a run from the Grand Canyon’s North Rim to the South Rim, at 4 AM in a futile attempt to avoid the skyrocketing temperature and finish before the sun became the determining factor in the success of our venture.…