53 hours in water - level 3
American swimmer Diana Nyad has become the first person to swim from Cuba to Florida without a shark cage.
The 64-year-old swam non-stop for 53 hours through shark-infested waters. When she reached the shore, hundreds of well wishers were cheering.
"I have three messages. One is we should never, ever give up."
Diana first attempted the swim in 1978 and then again in 2011 and 2012 but didn't make it across. For those who knew her, though, there was no doubt she would finish what she started.
"We've always known that Diana could do it. We've always known that. I knew that in 1978. All you have to do is know her, to know that she could swim from Cuba to Florida, if the waters were glassy, if the weather was right, if there were no beasts."
Diana's 110-mile swim has set the record for the longest ocean swim without a shark cage or flippers.
Difficult words: shark-infested (with a lot of sharks), attempt (try), glassy (without any waves), beast (dangerous animal), flippers (rubber things you put on your feet to swim faster).