Updated August 9 to reflect Phelps Gold-medal winning 200m Butterfly event.
Olympic swimmer Michael Phelps is such a superhuman powerhouse that scientists have studied him, in search of an answer for why Phelps — the most decorated Olympic athlete of all time — is so damn good.
Though Scientific American speculated in 2008 that the swimmer's "proportionally longer 'wingspan'" and double-jointed ankles could give him an extra boost, former sports medicine physician and swimmer H. Richard Weiner told the outlet at the time that, for the most part, Phelps is the product of hard work and skill.
Three days into the 2016 Rio Olympics — his fifth Olympic Games — the 31-year-old has yet to disappoint.
On Sunday, Phelps swam a speedy second leg in the 4x100 freestyle relay final, helping the United States team snag first place. The win marked Phelps' 19th time at the top of the Olympic podium.
Overall, the Baltimore native has 24 Olympic medals(20 gold medals) from four games, not including his 2000 Olympic debut in Sydney when a 15-year-old, braces-sporting Phelps pulled up fifth in his only event.
Here's a complete list of the Herculean swimmer's accolades, including some of his most memorable wins:
Phelps had his first breakout moment at the 2004 Athens games, breaking the world record in the 400 individual medley with a time of 4:08.26. He went on to break three Olympic records, claiming the gold in the 200 butterfly, the 100 butterfly and the 200 individual medley.
Phelps clinched two more gold with the 4x100 medley relay and 4x200 freestyle relay and then earned two bronze medals — two of the four nongold medals of his entire Olympic career thus far — in the 4x100 freestyle relay and 200 freestyle.
Phelps' record-breaking streak in the 2008 Beijing Olympics made his wins in Athens look like a quaint warm-up.
The athlete made a solid case for greatest of all-time, winning an unprecedented eight gold medals, kicking his way to world-record times in seven of those races and an Olympic record in the eighth.
The swimmer's nonstop wins helped him steal a title from from retired U.S. swimmer Mark Spitz, who held the record for most individual first-place wins during a single Olympic games.
Phelps kicked off the London Olympics with a fourth-place finish in the 400 individual medley and two silvers, in the 4x100 freestyle relay and 200 butterfly, a shaky start for an athlete who had dominated every event he entered just four years before.
But, of course, the swimmer finished strong, bringing in four gold medals: the 4x200 freestyle relay, the 200 individual medley, the 100 butterfly and the 4x100 medley relay.
The kicker? He wasn't really trying.
"I basically did that off of pure talent — very, very minimal work," Phelps told NBC's Bob Costas earlier this month.
These final first-place wins brought his gold-medal total to a whopping 18, cementing his status as the most decorated Olympic athlete.
In a 2015 interview with NBC Sports' OlympicTalk, Spitz said he predicted he would get "run over" by Phelps' success. "I still believe he's got gold medals in him," Spitz said.
He'd be right.
Phelps reemerged from a brief retirement to represent the U.S. in Rio. While there's little threat to his title as the greatest male swimmer of all-time, he's back to show the world he's still got it.
Phelps has already taken home two gold medals in Rio. One for the Mens 400 relay and the other in the 200m butterfly.
"It felt good to get, after my last 400 free relay of my career, this thing around my neck," Phelps told USA Today. "It feels good to get it back."