Katie Ledecky - the 18-year-old American prodigy who broke a world record without trying - is the most dominant swimmer alive

At just 18-years-old and only a few months removed from her high school graduation, Katie Ledecky is the best swimmer in the world. Some are even calling her the greatest freestyle swimmer of all-time.

At the FINA World Championships in Kazan, Russia, Ledecky accidentally broke her own world record in the 1,500m freestyle during a preliminary race in which she wasn't swimming her hardest.

"I wasn't kicking much," she said after the race.

After touching the wall, she seemed surprised to learn she'd set a new world record.

In the final of the same event one day later, she broke her own 24-hour-old world record by over two seconds, clocking in at 15 minutes and 25.48 seconds. For some context, in 2004, 19-year-old Ryan Lochte swam in the men's 1,500 at the US Olympic Trials and finished in eighth place. His time: 15:28.37.

Lochte is an 11-time Olympic medalist and arguably the best male American swimmer today, though he has found his success in shorter distance races. He has swam with Ledecky and confessed that she blew him out of the water.

"She's one of the best distance freestylers I've ever seen," Lochte told the New York Times. "I trained with her in Colorado once, and she made me look like I was stopping. She flew by me."

According to Bruce Gemmell, Ledecky's coach, part of the reason she's become so dominant is because she's adopted a different approach to the distance events. Rather than relying on endurance or sheer grit, Ledecky instead treats every race like a sprint.

"She's embraced the notion that all events can be swum with a sprinter's mindset," Gemmell told azcentral.com. "The longest event is 15 minutes and in the world of competition that's not a marathon or a triathlon. There has to be a sprint element involved."

In 2014, when Ledecky set the 1,500m freestyle world record for the first time - by over six seconds - USA Swimming National Team Director Frank Bush called Ledecky's performance "the most impressive race I've ever seen, and I've been in the sport for almost 50 years."

"There's nobody better at what she does," added swim analyst Rowdy Gaines.

In April, at the 2015 Arena Pro Swim Series: Mesa, Ledecky swam a forgettable 400m preliminary in 4:02.67. (Her world record in the event is 3:58.37.) That same day, Michael Phelps had swam the same event and finished in the exact same time of 4:02.67.

In a broadcast interview just after Ledecky had stepped out of the pool, Phelps - from the broadcast booth - challenged her to a race.

"Want to go in an hour?" Ledecky responded, laughing.

"No, I want to go right now, 'cause you're tired," Phelps, the record-holding 22-time medalist, quipped back.

Per OlympicTalk, Phelps went on to praise Ledecky after the interview concluded.

"I've watched her stroke so much, really, over the last couple of years," he said. "Really, she swims almost like a guy. Her long, loping stroke … stronger and stronger throughout the race. I think her stroke is so different from all the other females that she swims against."

Ledecky burst onto the scene at the 2012 London Olympics, winning the 800m freestyle in dominating fashion. She was just 15-years-old - the youngest gold medal-winning swimmer in London.

During the final lap of the Olympic final, Ledecky swam toward the wall in completely open water. The British commentators called her performance "one of the finest swims you'll ever see."

"This is somebody whose going to become very famous very suddenly," the commentators added quite presciently.

The 2012 Olympics was only the beginning. Ledecky has gone on to break nine world records in just the past two years. Currently, she holds the fastest times ever in the 400, 800, and 1,500m freestyles. This week at the World Championships, she has won the 400m and 1,500m freestyle.

Swimvortex.com had a nice roundup of the extent of Ledecky's dominance in her the three events. She has seven of the 19 fastest times ever in the 400m, eight of the 16 fastest times in the 800m, and six of the 14 fastest times in the 1,500m. She has also done it despite competing in an era where faster synthetic racing suits have been banned by FINA because they are believed to be performance enhancing.

Ledecky has committed to Stanford, though she won't enroll until in the fall of 2016. Over the next year she will train for, and likely dominate, the 2016 Summer Olympics in Rio. If she can continue her historic run of form, Ledecky will have had quite the Gap Year - and will be quite the college freshman.