Endurance swimmer Nyad moves from Cuba toward Fla.

In this photo provided by Diana Nyad via the Florida Keys News Bureau, endurance swimmer Diana Nyad swims in the Florida Straits between Cuba and the Florida Keys Sunday, Aug. 19, 2012. Nyad is endeavoring to become the first swimmer to transit the Florida Straits from Cuba to the Keys without a shark cage. (AP Photo/Diana Nyad via the Florida Keys News Bureau, Christi Barli)Open-water swimmer Diana Nyad pushed through dark waters early Monday as she tried to complete a record 103-mile (166-kilometer), unassisted swim without the aid of a shark cage.