Nik Wallenda has become the first person to walk across Niagara Falls on a highwire. Tens of thousands of people gathered at Niagara Falls and millions more were watching on television as the daredevil crossed high in the air above on a two-inch-wide 1500-foot-long wire strung over the raging waters. JUNE 15 2012. ABC TV NEWS NIGHTLINE. READ MORE: http://abcnews.go.com/Entertainment/niagara-falls-high-wire-walk-nik-wallenda-fulfill/story?id=16577963#.T9xwH5i1lJk