A decade ago, marathon swimmer and sports journalist Diana Nyad decided to complete one of the hardest swims in the world: the 110 mile trek from Cuba to Florida. At 60 years old, the swimming champion had tried the route before multiple times, and wanted to be first person to finish it without a shark cage. And to do it, she spent four years training with her coach, ex, and best mate Bonnie Stoll.

Since she finished her swim in 2013, the details have been constantly under scrutiny by the World Open Water Swimming Association (WOWSA), a body which has never certified the swim.

In the film Nyad, screenwriter Julia Cox has adapted Nyad's 2015 memoir Find a Way, with Free Solo filmmakers Elizabeth Chai Vasarhelyi and Jimmy Chin making their narrative feature debut.

"I have absolutely no doubt that Diana completed this swim," Cox told Vanity Fair. "When you’re at the top of your field as an athlete, you probably have to deal with criticism, no matter what. And Diana’s no stranger to that. But I have utter faith in the fact that she actually accomplished her goal. And there are always going to be people who are detractors."

In the film, Annette Bening takes on the role of Nyad, while Jodie Foster plays Stoll, promising (certified or not) one hell of a journey across the ocean.

How to watch: Nyad hits cinemas Oct. 20 and is streaming on Netflix Nov. 3.