The San Rafael Reef is a 30-mile long standstone wall barrier at the eastern edge of nowhere. For centuries, only the most intrepid travels found their way through its narrow slot canyons and into the forbidding landscape of the San Rafael Swell. Early Spanish explorers detoured 20 miles north to avoid this wall. Now, Interstate 80 runs right through it. On Interstate 70 near Spotted Wolf, Utah; May, 2015.