Katie Ledecky has won gold medals at this year's Olympics in the 200m and 400m freestyle. She also won gold in 2012, and holds three world records in swimming. But 10 years ago, when she was nine years old, she got an autograph and photo with another gold medalist swimmer: Michael Phelps. Back then Ledecky was an aspiring Olympian. And now she has won a gold medal on the same day as Phelps. That's quite a journey.

Here's the fantastic throwback: