Diana Nyad has become the first person to swim from Cuba to Florida without the help of a shark cage.
The 64-year-old stepped ashore in Key West, Florida, about 53 hours after she began her swim in Havana.
As she approached the shore, spectators surrounded her in the water, taking pictures and cheering her on. She swam within a few feet of the beach and walked on to dry land. She looked dazed and sunburnt.
It was Nyad's fifth attempt to complete the approximately 110-mile swim. She tried three times in 2011 and 2012. She also tried in 1978.
Her last attempt was cut short amid boat trouble, storms, unfavourable currents and jellyfish stings that left her face puffy and swollen.
"I am about to swim my last two miles in the ocean," Nyad told her 35-member team from the water, according to her website. "This is a lifelong dream of mine and I'm very very glad to be with you."
Nyad told supporters that a silicone mask she wore to protect her face from jellyfish stings caused bruises inside her mouth, making it difficult for her to talk.
Doctors travelling with her were worried about her slurred speech and her breathing, but they did not intervene.
Her journey began on Saturday morning when she jumped from the seawall of the Hemingway Marina into the warm waters off Havana. She stopped from time to time for nourishment.
"I admit there's an ego rush," Nyad said before the swim began. "If I - three days from now, four days from now - am still somehow bringing the arms up and I see the shore ... I am going to have a feeling that no one yet on this planet has ever had."
She wore a full bodysuit, gloves, booties and a mask at night, when jellyfish rise to the surface. Before the swim, she said the kit would slow her down, but she believed it would be effective.
The support team accompanying her had equipment that generated a faint electrical field around her, which was designed to keep sharks at bay. A boat also dragged a line in the water to help keep her on course.
Australian Susie Maroney successfully swam the Strait in 1997 with a shark cage, which besides protection from the predators, has an effect that pulls a swimmer along.
Last year, Australian Penny Palfrey swam 79 miles towards Florida without a cage before strong currents forced her to abandon the attempt. This June, her countrywoman Chloe McCardel made it 11 hours and 14 miles before jellyfish stings ended her bid.
In 1978, Walter Poenisch, an Ohio baker, claimed to have made the swim using flippers and a snorkel. Critics say there was insufficient independent documentation to verify his claim.
Nyad first came to national attention in 1975 when she swam the 28 miles around the island of Manhattan in just under eight hours. In 1979 she swam the 102 miles from North Bimini, Bahamas, to Juno Beach, Florida, in 27.5 hours.
She is also an author of three books, is a motivational speaker and has been a reporter.