U.S. Teen Swims Nearly a Mile Faster Than Many People Could Walk It

KAZAN, Russia (TheBlaze/AP) -- American teenager Katie Ledecky has improved her own world record in the 1,500-meter freestyle at the swimming world championships.

The 18-year-old Ledecky completed the marathon-like race in 15 minutes, 27.71 seconds — shaving 0.65 seconds off the mark she set at last year's Pan Pacific championships in Australia.

Katie Ledecky of the United States competes in the Women's 1500m Freestyle Heats on day ten of the 16th FINA World Championships at the Kazan Arena on August 3, 2015 in Kazan, Russia. (Adam Pretty/Getty Images)

The swim came during morning heats Monday. She'll have a chance to improve it again in Tuesday's final.

#swimming @katieledecky's new WR in Women's 1500m Freestyle is 15:27.71! YOU GO GIRL! #finakazan2015 #FINAworlds pic.twitter.com/sFSruLE9mS

— kazan2015 (@finakazan2015) August 3, 2015

It's the fourth time Ledecky has broken the record in the 1,500. She also holds world marks in the 400 and 800 free.

—