Long-distance ocean swimmers have it rough. They brave rough seas, sharks, jellyfish, and other challenges to pull off their grueling feats. But few face bigger challenges than Philippe Croizon, who has just completed a swim from Alaska to Russia — even though he has no arms or legs.  And this is just the latest in a series of stunning achievements for the French athlete. Here, a brief guide to Croizon's exploits, and the message he's hoping to send to the world:

First off: How can a man with no limbs swim?
He propels himself through the water using flippers attached to prosthetic legs. (See a video below.)

How far did he swim?
The 44-year-old paddled from Little Diomede island in Alaska to the waters off Big Diomede in Russia (which wouldn't let him come all the way to shore), becoming the first limbless swimmer to accomplish the feat. He made the 2.5-mile swim in an hour and 20 minutes. Oh, and the water in the Bering Strait that day was a beyond-chilly 39 degrees Fahrenheit. "This was the hardest swim of my life," Croizon said.

Was this his first long-distance swim?
Far from it. In fact, the trip from the U.S. to Russia was the final stretch of a much more impressive three-month feat. Croizon, who lost his limbs in an electrical accident in 1994, and his friend and swimming companion Arnaud Chassery, also swam from Papua New Guinea to Indonesia, crossing from Oceania to Asia; across the Red Sea from Egypt to Jordan, between Africa and Asia; and from Spain to Morocco, between Europe to Africa. The Bering Strait swim took them from the Americas to Asia, completing an effort to conquer waterways separating continents.

What made him attempt such a daunting feat?
Croizon and the nonprofit organization that helped support the endeavor, Handicap International, wanted to send a message. "Just to say that nothing is impossible," Croizon said. "We can all succeed in life despite of what happens to us. There is no difference. We are all equal."

Sources: AFP, Alaska Dispatch, Daily News, Telegraph

Below, take a look at Croizon braving the icy waters: