Christi Barli/AFP/GettyImages via Newscom

The fourth time is not the charm for Diana Nyad. The long-distance swimmer, who turns 63 today, was pulled from the water yesterday at just before 1am (EST) nearly halfway through her attempt to swim solo from Havana, Cuba to Key West, Florida, the southernmost U.S. island. This was Nyad’s fourth try at the swim, after an attempt in 1978 and two in 2011 were cut short. Still, Nyad swam farther, and for more hours on this attempt than on the three previous ones.

During the course of her 103 mile journey, Nyad endured scores of painful jellyfish stings, strong currents, choppy waters, violent storms at sea and the threat of sharks. She suffers from asthma, so the risk of an asthma attack was always present as well. She had to stop frequently during the swim, to be treated for jellyfish stings or to wait out powerful squalls. Finally, the combination of bad weather, jellyfish stings and circling sharks proved to be too dangerous for Nyad, who wanted to press on despite the urging of her crew to abandon the swim.

Though Nyad’s latest attempt to cross from Cuba to Florida lasted just 42 hours, the reality is that she’s been on the journey for more than 30 years. The swimmer’s first attempt to cross the geographic, cultural and political divide between Cuba and the U.S. came in 1978, when she was just 29 years old. Nyad was already famous for long distance swimming, having crossed Lake Ontario, the Bay of Naples, and circled the Island of Manhattan in record time. But the 103 mile distance between Cuba and Key West was the greatest challenge she had yet to undertake. Nyad set out from Cuba in a shark cage, and the 8-foot waves repeatedly bashed her against the side of the cage and set her and her lone escort boat horribly off-course. She was pulled from the water, dehydrated and disoriented, just 42 hours into her swim. The crushing defeat haunted her for 30 years, long after she’d retired from distance swimming.

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In 2011, at age 61, Nyad announced that she would undertake the Cuba-Florida swim once again. But an attempt in August and another in September of that year were thwarted due to bad weather, and jellyfish stings that compromised Nyad’s respiratory system and left her unable to catch her breath.

During this latest attempt, which Nyad undertook with no shark cage, no wetsuit and no flotation devices, she was accompanied by a small army of 25 monitors, escorts and medics, all ready to ward off sharks, warn of upcoming squalls and treat painful jellyfish stings. Still, when it came down to it, it was just Nyad alone in the water—the rules of long-distance swimming dictate that she couldn’t exit the water, or hold onto the boat or another person for support. Even when she took meal breaks, she ate and drank in the water, from a plastic tube.

In the end, the elements might have bested Nyad, but there is still great victory in her defeat. Nyad, at 63, has shown the world that the human spirit can accomplish great achievements, and that age is just a number.