From the Flying Wallenda's website:
"It was during a promotional walk in San Juan, Puerto Rico, in March, 1978, that the patriarch of the Great Wallendas fell to his death at age 73. Not because of his age or capabilities, not because of the wind, but because of several misconnected guy ropes along the wire. Karl once said, "Life is being on the wire, everything else is just waiting." The Wallenda legacy lives on to the sixth and seventh generations through Karl's grandchildren and great-grandchildren."
This info is not true. See this TIME magazine article:
http://www.time.com/time/magazine/article/0,9171,919500-2,00.html
Excerpt:
"The wind is my worst enemy," Wallenda once said of his outdoor performances. Last week, as he prepared to walk a wire strung 300 ft. between two beachfront hotels in San Juan, P.R., he was warned that the winds blowing in off the sea were tricky. There was a steady breeze of 12 m.p.h., but with gusts up to 23 m.p.h.
"Don't worry about it," said Karl as he checked the wire at the tenth-floor window, some 100 ft. above the sidewalk. "The wind is stronger on the street than up here."
Karl Wallenda was 73 by now, but still strong, hard-muscled, his eyes a bright blue, his gray hair tufted around his ears. He had said he would make the walk, and so he would. There were 200 people watching. Among them was his granddaughter Rietta, 17, the only relative then performing in his act.
Wallenda had no sooner started than a gust of wind made the cable vibrate. Wallenda stopped, steadied himself. A hush fell over the crowd.
He started again, crossed a little more than halfway. The cable began to sway. Wallenda leaned forward to keep his balance. One young member of his troupe, waiting on the roof at the far end of the wire, warned him to crouch down for better balance.
"Sit down, Poppy, sit down!" the youth cried.
Wallenda started to crouch. A gust of wind suddenly jarred him. Then, as the horrified crowd watched, he started to fall, very slowly at first. He reached out for the cable with one hand, but he was still holding the balancing bar and could not get a grip on the cable. Down he went, still holding onto the pole. Ten stories below, he landed on the roof of a taxi and bounced off onto the sidewalk. At the hospital, he was pronounced dead of massive internal injuries.
This is the video:
http://www.metacafe.com/watch/66324/rope_walking_accident/