IMAGE DISTRIBUTED FOR DISCOVERY COMMUNICATIONS - Nik Wallenda walks over the Chicago River uphill nearly 8 stories for Discovery Channel's Skyscraper Live with Nik Wallenda on Sunday, Nov. 2, 2014. (Jean-Marc Giboux/AP Images for Discovery Communications)
IMAGE DISTRIBUTED FOR DISCOVERY COMMUNICATIONS - Nik Wallenda walks over the Chicago River uphill nearly 8 stories for Discovery Channel's Skyscraper Live with Nik Wallenda on Sunday, Nov. 2, 2014. (Jean-Marc Giboux/AP Images for Discovery Communications) Jean-Marc Giboux Associated Press
IMAGE DISTRIBUTED FOR DISCOVERY COMMUNICATIONS - Nik Wallenda walks over the Chicago River uphill nearly 8 stories for Discovery Channel's Skyscraper Live with Nik Wallenda on Sunday, Nov. 2, 2014. (Jean-Marc Giboux/AP Images for Discovery Communications) Jean-Marc Giboux Associated Press