Charles Blondin, AKA The Great Blondin, was a 19th century French acrobat and tightrope walker. In 1859 he became the first person to traverse 1100 feet across the 160-foot high gorge beneath Niagara Falls on a tightrope. In a demonstration of his skill, he then did it several more times including being blindfolded, pushing a wheelbarrow, wearing stilts, and carrying a man on his back.
After demonstration of his skill it is easy for many people to believe that Blondin could cross the wire with a person riding on his back.
It is a totally different thing to be trust him enough for you to be the volunteer to be carried on his back across the chasm…