Karl Wallenda is probably the world's most famous high-wire walker. It was his daring in developing the seven-man-high pyramid that put the name Wallenda on the pinnacle of circus fame. When his terrifying act collapsed from 40 feet killing two members and crippling a third young man for life it seemed that the Wallenda dreams were over, but his leadership broke through all family objections to restore the performance one year later. In July of this year Karl Wallenda , at the age of 65, once again challenged death - this time on his own. He attempted a walk over a 700-ft gorge, a thousand feet wide in North Georgia, with no possible means of saving himself should he slip. Tonight's film is the story of Karl Wallenda and a fantastic day of show business in the hot sun. Commentary spoken by JOHN STOCKBRIDGE Produced by PHILIP LEWIS (Defying death: page 4)