Sixty-one-year-old American swimmer Diana Nyad ended her bid Tuesday to swim the Florida Straits from Cuba to the United States. Nyad was attempting to become the first person to make the 165-kilometer crossing without the benefit of a shark cage.

According to her Twitter account, Nyad was forced to end her attempt at the record-setting swim after 29 hours at sea. A spokeswoman announced the swim ended due to a combination of factors including high winds. The swim was to last an estimated 60 hours.

Nyad attempted the same swim in 1978 at the age of 28, but ended that attempt due to high winds and rough seas. Australian swimmer Susan Maroney completed the swim in 1997 with the help of a shark tank. Maroney was 22 years old at the time.