People do crazy things all the time, but sometimes these things are borderline unbelievable. Here’s a sampling of some of the most amazing swimming feats humans have achieved.

Hold Your Breath

 
I’m sure you’ve seen kids have contests to see who can hold their breath the longest. Well, apparently some of those kids never grow out of it. In swimming, it’s known as free-diving, and it turns out there are about 9 different competitive variations.
 
 
One variation is Static Apnea (breath-holding). This is a timed event where competitors see who can hold their breath the longest while submersed in a pool. German-born Tom Seitas broke the world record for this event in spring 2012. While floating in a pool of water, he held is breath for a total of 22 min 22 sec. Part of this success is due to the fact that he filled his lungs with pure oxygen, and the other part to the fact that his lungs are 20% larger than normal.
 
Another popular free-diving competition is Dynamic Apnea, with or without fins. For this competition, swimmers see how far they can swim on one breath. In the No Fins category, Tom Seitas was tied at 213 meters with Dave Mullins until 27 September, 2010 when Dave Mullins broke that record with 218 meters in 4 min 11 sec.
 

Olympic Speed

 
Ok, so Michael Phelps became a world-known swimming icon after his record-breaking streak at the 2008 Olympics. But what about Ye Shiwen?
 
She’s a 16 year-old Chinese swimmer who competed in the 2012 London Olympics and broke a world record too. She competed in both the 200 and 400 Individual Medley events in London. She broke the Olympic record for the 200m IM, but the real shock came when she broke the world record for the 400m IM at 4:31.73. Controversy ensued over this win because it was a whole 5 seconds faster than her previous personal best. Many accusations of doping flew around, but the record has been upheld as she passed all needed tests. Instead, her improvement has been contributed to a growth spurt.
 

 Big River Man

 
While most swimming records are completed in pools, lakes, or oceans, that’s not Martin Strel’s style. He’s famous for his many river swims. Starting in his home country of Slovenia, his first big river was the Danube in 2000. This 1,780 mile swim earned him the Guinness World Record for the longest swim.
 
He broke his own record two years later when he swam the entire Mississippi River (2,414 miles), and then again a year later swimming the Parana River (2,484 miles) in Argentina.
 
Most people would think this was enough, but not Martin. In 2004, he added the world’s third longest river, the Yangtze River (2,487 miles), to the list. He swam the entire length of the river in 40 days.
 
He decided to tackle the Amazon for his next challenge—piranhas and all. In 2007, at the age of 52, he swam the entire length of the Amazon River (3,273 miles) in 66 days. This epic swim was documented in the film Big River Man, which won a Sundance film festival award for cinematography.
 
 

And the Winner is…?

 
This one is still prepping for a potential record-breaking swim, but frankly his attempt deserves recognition, even if he doesn’t succeed.
 
Benoit (Ben) Lecomte is a French-born open water long distance swimmer. He first made history in 1998 when he crossed the Atlantic Ocean without a kickboard. Having achieved this, he’s out for a new challenge- the Pacific Ocean. He is dedicating the swim to the fight against cancer, along with working together around the world to achieve goals. This legendary attempt will start in Tokyo and finish in San Francisco, covering 5,500 miles.
 
His journey is planned for later this year and will be documented by a 24/7 live-streaming broadcast by Ridgeline Entertainment, The Longest Swim. You can follow his progress here.