Last year he tackled Niagra tightrope walker Nik Wallenda, 7th generation member of the famous Flying Wallendas, is planning his next feat. He's practicing in his hometown of Sarasota, Florida for a quarter mile walk across The Grand Canyon! No tethers or safety nets...just the Colorado River 1500 feet below! Nik's walk is scheduled to be shown live on the Discovery Channel this Sunday June 23rd. 

Here's video of Nik practicing!