Ben Friberg's Florida Straits paddle board challenge begins
2 August 2013 Last updated at 02:13 BST
An American man has set off from Havana in a bid to become the first person to cross the Florida Straits in a day - standing on a paddle board.
A number of swimmers have previously attempted to cross the straits but have failed.
Ben Friberg, 35, from Tennessee, faces strong currents, potentially choppy water and sharks on his journey.
Sarah Rainsford reports from Havana.