Plus, the gold medal-winning swimmers get emotional in tributes to their time in Rio.
At least social media is good for something during the Olympics. (Side-eyeing the haters.)
As if we didn't have enough reasons to love Michael Phelps and Katie Ledecky for, you know, winning a billion gold medals and possibly being half mermaid, the duo recreated an adorable decade-old picture of a then 9-year-old Ledecky getting an autograph from Phelps. Only this time, he stepped up to get an autograph from the breakout star of Rio.
RELATED: Michael Phelps Explains Why He's Really Retiring After Rio: 'This Is What I Came Back For'
Ledecky took to her own Instagram to give a big, emotional goodbye to the Games. After winning four gold medals and a silver, the 19-year-old swimmer wrote, "This picture captures the joy I have had this past week in representing the USA...I'm happy to be bringing home some medals and memories!"
Meanwhile, Phelps took home five gold medals and a silver, cementing his status as the most decorated Olympian of all time. He shared a photo with his teammates and wrote, "Wow! The best way to finish! It has been an honor to represent the USA! A true dream come true!!!"
Rio also marks Phelps' official retirement, with the swimmer explaining his decision to Bob Costas, "This is what I came back for. At the age of 31, I'm happy to start moving forward into a new chapter of my life. I am retiring, this is it. That was the last race ever."
In other adorable moments from the Olympics, Phelps got choked up over having his son, Boomer, watch him win gold. Check it out in the video below.