MICHAEL PHELPS: Here's a look at the historic career of the greatest Olympian ever

Michael Phelps seems to be enjoying himself at his fifth Olympic Games.

For the first time in his career, he walked in the opening ceremony. He's already won four gold medals, and could add a fifth to give him 23 career gold medals (and 27 total medals). He's been surprisingly emotional on the podium, as if the scope of his achievements - and that his swim career is coming to an end - is finally dawning on him.

In honor of Phelps' latest Olympic success, we took a look back (in 26 slides for his 26 medals) at how Phelps went from being a gangly Baltimore kid to the best Olympian of all-time. It's been a journey of peaks and valleys, but Phelps, at 31, seems to finally have figured it all out.