As Katie Ledecky pulled herself out of the pool following her 800m victory, she raised an arm and saluted the crowd.

And, as they have done so many times before in her illustrious career, the crowd rose as one to salute a living legend.

In London, a 15-year-old Ledecky won her first Olympic title in the 800m freestyle.

Now, 12 years later, she has a fourth gold in that event.

Six male Olympians have won four Olympic titles in the same event: Paul Elvstrøm, Al Oerter, Carl Lewis, Michael Phelps, Mijaín López and, at this Games, shooter Vincent Hancock.

Ledecky joined Japanese wrestler Kaori Icho as the only two women to do it.

That alone marks Ledecky as one of a kind — a special swimmer of the highest calibre.

That legacy of excellence is not limited to Olympic Games. The 27-year-old has won a whopping 21 World Championship titles in her career, 15 of them in individual events.

She has never, ever, lost a race over 800m at world level, with nine total gold medals from Worlds and Olympic Games.

Up on the podium, there was no flickering of emotion from Ledecky other than the broadest of grins as the Star Spangled Banner played.

Perhaps she's just used to hearing it by now.

"I try not to think about history very much," Ledecky said after winning her 1,500m title earlier in the meet.

"I know those names, those people I'm up with. They're people I looked up to when I first started swimming. So it's an honour to be named among them. 

"I'm grateful for them inspiring me. There are so many great swimmers that have helped me get to this moment."

And despite personal best times from her two closest rivals, Ariarne Titmus and American Paige Madden, Ledecky held them off to claim yet another Olympic title.

Ledecky now has the joint-most golds by a female Olympian, with former Soviet gymnast Larisa Latynina, and is the United States' most decorated female Olympian.

Two of this generation's greatest rivals, Ledecky and Titmus, were once again locked into an epic battle through the first half of the race.

Looking into each other's lane heading down the second 50m of each 100m, it appeared as if the pair were egging each other on, Ledecky turning at the 200m mark 0.71 seconds under world record pace, Titmus not far behind her.

At the Australian swim trials, Titmus was swimming at Ledecky-like pace before dropping off in the second half of the race.

And the same pattern emerged through the first three quarters of this race, with the pair going stroke for stroke, Ledecky's rate slightly higher than Titmus.

But between 550m and 600m, Titmus cracked.

Suddenly Ledecky had a body length advantage, and Titmus had Madden to contend with for the silver medal after the American sneaked up on the Australian's shoulder.

Titmus held on for silver, her fourth medal of the Games and eighth overall.

While Ledecky, the doyen of women's swimming, sealed a special quartet of victories, it was shown that she is not invincible. 

Her third-placed finish in the 400m earlier in the meet was her first and only Olympic bronze medal.

Titmus has provided some knocks to that illusion of invincibility that the American has worn over the early part of her career.

And even in this, her pet event, she has suffered defeat, albeit just once.

But it goes without saying that to be at the top of your sport at the biggest events for over a decade takes something extraordinarily special.

Canadian teen phenom Summer McIntosh is the one person who has handed Ledecky defeat in the 800m over the past 13 years, beating her at the Southern Zone South Sectional Championships meet in Orlando, Florida in February.

McIntosh is not competing in the 800m at this Olympics and, frankly, it's difficult to imagine that all the women in the 800m were not thankful she decided to opt out given the way she's performed at these Games.