Update 22 Feb 2021: Added that Webb attempted to cross the Niagara River below the falls, not above them (thanks to information provided by a well-informed reader).
In the summer of 1976, Diana Nyad flies to England…
happily accompanied by my two closest friends . . . and by an American film crew of seven. We were off to make, assist, and record history. I was attempting to become the first woman to complete the double crossing of the English Channel. (Other Shores, 1978, p. 121)
During the flight, Nyad reads the Channel Swimming Association (CSA) handbook. “Who knows the story of Captain Matthew Webb . . . ?” she paraphrases:
Webb was the first to swim across. . . . Some weeks later Webb tried to cross the Niagara River four hundred meters above the falls; he is buried at the bottom. (p. 122)
The way Nyad describes it, Webb barely had time to dry off before steaming across the Atlantic. Once in the U.S., he’d have to race for Niagara and immediately jump back in the water.