Wallendas have rich history, not without tragedy

When Nik Wallenda sets out for his tightrope walk over Niagara Falls late Friday, he'll be adding another chapter to his family's storied daredevil history which dates back more than two centuries. Wallenda has said he is disappointed he is being made to wear a tether by the event's sponsor, ABC, since his family has performed over the years without such safety precautions.