Diana Nyad attempts Cuba to US swim record
19 August 2012 Last updated at 15:10 BST
A 62-year-old American woman is making her fourth attempt to become the first person to swim from Cuba to the US without the protection of a shark cage.
Diana Nyad has already been stung several times by jellyfish but is continuing her 166km (103 mile) journey, team members said.
She left the Cuban capital, Havana, on Saturday afternoon and is aiming to reach Florida on Tuesday.
She is relying on an electronic shield as a shark deterrent.