Chloe McCardel is no stranger to swimming long distances.

An endurance swimmer, McCardel has crossed the English Channel multiple times, including two double crossings. But like other endurance athletes, McCardel is not satisfied with doing something that's been done before.

So next week the 27-year-old Australian will attempt to pull off a feat that's never been done. She's going to try to swim from Cuba to Florida without a shark cage.

"It has to be the greatest challenge in the world at the moment," McCardel said when she announced the challenge on "Today."

The 105-mile swim is expected to take between 55 and 60 hours. During that time, McCardel will not be able to use a flotation device or anything that would help her move forward. She'll be accompanied by a crew of 32 people on a nearby boat, but she won't be able to touch the boat.

McCardel isn't the first person to attempt to challenge. American Diana Nyad has tried four times, most recently last August. But Nyad's swim was cut short when she had to be pulled from the water after several jellyfish stings. Susie Maroney, an Australian woman, completed the journey in 1997 using a shark cage.

Because McCardel will be attempting the swim earlier in the summer, she and her team are hoping to avoid the copious jellyfish. Still, even without having to worry about jellyfish, McCardel knows that she'll have plenty on her mind.

"You’re extremely exposed to the condition of the water," McCardel told USA Today Sports. "You can’t build a tent or rest up and have a nap. You can’t slow down or have a rest. While I’m feeding, I tread water. It’s quite tiring to be upright in the water treading water and having a feed."

McCardel called the trek the "last bastion of true marathon swimming," and a world record is certainly in her sights. But this swim is about more than that. McCardel's mother is a cancer survivor, and McCardel hopes to use her publicity to encourage people across the world to donate to various cancer organizations.