Sharks, jellyfish stings, tropical storms, navigation problems and physical exhaustion are the kinds of issues that fortunately don't trouble the average person during a standard day at the office. For retired athlete Diana Nyad, however, these were the very challenges she faced during the several attempts she made, in her early 60s, to become the first person to swim the 110 miles from Cuba to Florida without the use of a protective cage. Most people, including Nyad herself, thought she had retired from competitive swimming at the age of 30.