Lesbian athlete Diana Nyad is swimming from Havana to the Florida Keys today.
The 61-year-old former NPR commentator left Havana on Sunday evening. The 103 mile swim will take 60 hours, or about two-and-half days.
She has to swim without a wetsuit; water temperatures will be in the 80s.
Another challenge this time around will be sharks. Nyad is going to swim without a shark cage; instead, boats will surround her and pump protective electric currents into the water. She'll also be accompanied by divers and kayakers who will scare the sharks away.
Only one other person has completed this swim before, and that woman did it inside a shark cage.
Nyad has tried to do this swim before -- in the 1970's, when she was a lot younger. She had to abandon that attempt after 40 hours.