Hayes Street, is in one word, exhausting. It is five blocks of increasing steepness (11.15% grade at its steepest), and is considered to be one of the most daunting hills in all U.S. races, according to Runner’s World. I can attest to just how exhausting this .67 mile incline is. Coming up to the hill, all you can see is a sea of colors making their way up, up, up. Runners train in preparation for this infamous hill. This year, at the 102nd Annual Bay-to-Breakers