Tightrope over gorge at Grand Canyon: Nik Wallenda's 'tricks' are incredible balance and arm muscle endurance
Monday, June 24, 2013 - 13:30
in Earth & Climate
Nik Wallenda, who completed a 1,400-foot tightrope walk over a river gorge near the Grand Canyon on live television is not super-human despite his successful feat, according to experts.