American Tim Freriks remembers visiting the world famous Grand Canyon as a child. He recalls looking up from the very bottom of the Grand Canyon at the huge walls of rock hundreds of meters above his head. At the time, Freriks was not excited about the long walk back to the top. And he never imagined he would one day run up the trail along the side of the canyon’s walls. Freriks had that childhood memory after he ran from the canyon’s North Rim to the South Rim. He finished the 34-kilometer rim-to-rim run with what is called the fastest known time, or FKT. There was no prize -- only the unofficial record for the fastest race time. This kind of award has become a goal for athletes in all kinds of activities on trails, mountains and mountain cliffs.