I am large, I contain multitudes. Walt Whitman, “Song of Myself”

From afar, rivers can take on a homogeneous appearance. I remember standing on the south rim of the Grand Canyon once, looking down on the Colorado River thousands of feet below. From that viewpoint, it looked like an impossibly blue ribbon that had been carefully placed on the rust-orange of the canyon floor. No variations were apparent, nothing to suggest movement, impediments, or dynamism. Yet, after two hard days of hiking, I saw a very different river as I stood next to the raging torrent of its shores. Here, the Colorado was no decorative ribbon, it was alive, pulsing, charging, and shifting in seemingly endless directions with color patterns of foam, soil, and sky. Understanding such as this required intimacy and exploration. It could not have come from the rim, no matter how carefully I observed or how long I spent. Standing on the rim of the Grand Canyon, one can easily take much for granted. How hard it will be to hike down (and, more importantly back up). How hot it is down on the canyon floor. How dynamic the landscape becomes during a sudden rainstorm. To really see the Grand Canyon and the main shaping force of the Colorado River, the rim is not sufficient. And yet, the vast majority of tourists and visitors to the national park never leave the rim. They arrive in cars, pull over at various lookout points, take in the scenery, snap a few photos, and drive off having never ventured down into the details.