US swimmer Diana Nyad attempts to swim from Cuba to Florida
1 September 2013 Last updated at 02:24 BST
US endurance swimmer Diana Nyad is again trying to become the first person to swim from the Cuban capital, Havana, to Florida without a shark cage.
Her last attempt, a year ago, was hampered by rough seas and jellyfish stings.
The 64-year-old says this will be her fifth and last try to cross the 166km-wide (103 mile-wide) Florida Straits.
Sarah Rainsford reports from Havana.