Workers Dangling 4,000ft To Clean Grand Canyon SkywalkDangling 4,000 feet in the air, crews clean the underside of the Grand Canyon catwalk. KPNX reporter Krystle Henderson has the story.Get more newsLiveonPrintJune 20, 2014, 4:33 PM UTC / Updated June 20, 2014, 6:26 PM UTC