Swimming across the Atlantic
Direct copypaste from Wikipedia;
Benoît Lecomte (born 1967) is a French long distance swimmer who was the first man to swim across the Atlantic Ocean without a kick board in 1998. He did this to raise money for cancer research as a tribute to his father. During his 3,716 mile journey in 73 days, he was followed by a support boat that had an electromagnetic field for 25 feet to ward off sharks. He did, however, still encounter sea turtles, dolphins, and jellyfish.
The feat took him 72 days, with 6–8 hours spent swimming each day in sessions of about two hours' length. He was accompanied by associates in a boat, where he could rest and eat between each swimming period. The swim extended from Hyannis, Massachusetts to Quiberon, Brittany, France. He stopped for 1 week in the Azores, a Portuguese archipelago in the Atlantic Ocean.
Which is nothing compared to Guy Delage;
Guy Delage claims he is the first person to swim solo across the Atlantic Ocean (with the help of a kick board, from the Cape Verde Islands to Barbados). 16 December 1994. Logging six to eight hours a day behind a 15-foot raft that carried his communications gear and food supply, Delage ate and slept on the craft when not in the water. After 55 days he had covered 2,100 nautical miles.
Which Wikipedia considers the easier trip as he had a raft with a propulsion system; however, he did it alone and without any "electromagnetic fields", which marks him as the better guy in my books.