Around this time in 2014, during the summer smack in-between the 2012 London Olympics and 2016 Rio Games, Michael Phelps announced his comeback from retirement. The news was met with jubilation from sports fans. The greatest swimmer of all-time, making one last Olympic journey. Many were elated.

Not only would that comeback mean that Team USA was suddenly much, much stronger: It would also be one last chance to see that greatest swimmer of all-time swimming and competing in a stroke he had owned since emerging onto the international scene: butterfly. Since 2000, Michael Phelps and butterfly were synonymous: Whenever you think of Phelps, you think of his butterfly stroke charging forward through the water, mouth open, coming home. It’s been a relationship made in Olympic gold heaven.

Every single time Phelps raced in butterfly in a championship, I reminded myself that we may never see another human swim like this again. Not in a generation, at least. Not like this. Similar to the kinds of sentiments people must have felt when seeing Janet Evans scorch the record books back in the 1980s. Greatness is rare, but when we see greatness, we instinctively know — and must watch.

It is with this echo of “greatness” that I’m reminded we are witnessing a swimmer equally as dominant, if not more, than Michael Phelps was in butterfly — Katie Ledecky and freestyle. Ledecky, like Phelps and Evans, has not only re-written the record books, but she has also re-written our expectations and perceptions of what greatness really is. Often, the question isn’t, “Will Ledecky win?” but “By how much?”

Every time Michael Phelps raced butterfly, we were drawn towards watching that very event. Every 100 and 200 butterfly and 400 medley relay became “Can’t Miss” material. Because we knew we might not see it again. Because we knew a legend was competing before our very eyes. Likewise, when Ledecky first burst onto the scene in 2012 as a 15-year-old newcomer Olympic gold medalist, we knew we were witnessing something special. Over the years, we’ve realized just how special.

This weekend at the 2018 TYR Pro Swim Series in Indianapolis, Katie Ledecky returns to the long course waters in a mid-Olympiad summer season. She’s scheduled to compete in a slew of freestyle events. I’m reminded of that similar feeling from four years ago, watching Phelps compete in the 100 butterfly, thinking that we may never see someone swim this event, like this, in our lifetimes. And now? That event is the women’s 800 freestyle.

I’ve often wondered, when the goggles are hung the final time, which event of Katie Ledecky’s incredible repertoire will go down as her best. The 1500? Possibly. Though this event may stand out because of Ledecky’s sheer domination of her competitors. The 400? Another possibility. Ledecky’s WR in this event could stand for a generation. But for me, that 800 freestyle is the mid-point between that dominant mile and that jaw-dropping 400 time. Like Phelps’ 200 butterfly, it’s the event where Ledecky first had major international success.

Throughout the years, so many swimmers have put their signature on certain events, but none quite so like Ledecky and that 800 freestyle.

This weekend is one more opportunity to witness a unique kind of greatness. That word gets thrown out with regularity these days, but when it comes to Legendary Ledecky, we may never see another swimmer as dominant in our lifetimes. It’s a rare opportunity, like watching Michael Phelps churn down the pool in perfect harmonious butterfly strokes, to witness something one-of-a-kind, and one-of-a-generation.

Don’t miss it.