We’re on the ground in Rio covering the 2016 Summer Olympics. Check out all our coverage here.

While Michael Phelps’s winning of his 19th gold medal may be the feel-good story of the swimming pool not involving Yusra Mardini so far, the most significant development of the opening weekend of swimming is surely the sport’s renewed assault on the record books.

The ban of full-body non-textile (“LZR”-style) swimsuits at the end of 2009 had a dramatic effect on the pace of records broken in swimming. Of 32 events contested in the 2008 Olympics, 27 had records broken in 2009; in 2010, none did. But time marches on, and athletes improve. The London games in 2012 saw records broken in eight events — a far cry from the 19 events that saw records fall in Beijing, but a step in the right direction.

If the first weekend of action in Rio is any indication, the swimming world has recovered, with a vengeance. Of the eight swimming events completed so far, five have led to world records, including one of two relays (women’s 4×100), and four of the six individual events (all three women’s and one of three men’s). Here are the most dominant individual swims from the first two days of competition, ranked:

4. Sarah Sjostrom — 100-meter butterfly

Swedish 22-year-old Sarah Sjostrom is a name to remember. In particular, she has the fastest 200-meter freestyle time of any woman since 2012, and is thus probably the most likely to play spoiler to Katie Ledecky’s hopes of winning three individual golds when the two face off in that event Tuesday.

Sjostrom looks even stronger after kicking off her meet with a world record. She originally set the 100-meter butterfly record in 2009 (at age 15!) but wouldn’t match her pre-ban time again until 2015, when she reclaimed her record from Dana Vollmer (who had taken it in 2012).

Sjostrom finished in 55.48, nearly a full second clear of second place, and a half-second clear of the next-fastest woman ever. Usually, that would be a pretty amazing showing, but this was a big weekend for amazing showings.

3. Katinka Hosszu — 400-meter individual medley

Katinka Hosszu, the 27-year old Hungarian, is the only swimmer on this list who broke a record that wasn’t already her own. She very nearly broke it in her preliminary heat, and then destroyed it in the final:

Hosszu won the race by nearly 5 seconds – finishing in 4:26.36 – and cleared Ye Shiwen’s record by nearly 2 seconds. Though few expected a performance this great, Hosszu didn’t come out of nowhere. She was world champion in this event in 2009 and 2015, and has held the short-course record in it on and off since 2013.

2. Katie Ledecky — 400-meter freestyle

If there was any distance at which it seemed Katie Ledecky’s best times might have been flattening out, it’s the 400-meter freestyle, where she hadn’t broken the world record since 2014. Following unexpectedly fast 100 meter splits in the 4×100 relays and almost breaking her record in her preliminary heat, however, another record seemed inevitable. And then this happened:

LOL Katie Ledecky was celebrating and people hadn't finished yet pic.twitter.com/qCaDbu2kSg — Isaac (@WorldofIsaac) August 8, 2016

Ledecky’s 3:56.46 was 4.77 seconds faster than second-place Jazz Carlin, and nearly 2 seconds faster than her own 2014 record (3:58.37). It’s over 4 seconds faster than any woman has swum in the post-ban era (4:00.65 by bronze-medalist Leah Smith this year). The only other woman ever to swim below 4 minutes in this event is Federica Pellegrini, who did it in 2009. Ledecky is getting closer and closer to making 400 meters a sprint distance: Her speed of 59.1 seconds per 100 meters is closer to the average speed of the 50 fastest 200-meter swimmers than it is to the average of the 50 fastest 400-meter swimmers. Her speed in the 800 is already faster than all but a handful of women in the 400, and her speed in the 1,500 is faster than anyone’s but hers in the 800:

Given her 100 splits (not reflected), and 200 and 800 races still to come (there is unfortunately no 1,500-meter women’s event at the Olympics), expect this curve to fall even further into the absurd.

1. Adam Peaty — 100-meter breaststroke

Adam Peaty may not have the most versatile program, and certainly didn’t generate as much buzz as Ledecky or Hosszu, but for one race at least, he was every bit as dominant. He initially set a record in his preliminary heat, which generally bodes well. His final time of 57.13 won his race by 1.56 seconds and broke his pre-Olympic record by 0.79 seconds, and puts him 1.33 seconds clear of his next-fastest competitor ever.

For a 100-meter race, this is crazy good – even against this crazy competition. To show how much so, I plotted the top 50 times since 2010 for each of these four records, in standard deviations from the mean:

Ledecky’s 400-meter race was a thing of beauty, especially considering that 400 meters is supposed to be her third-best distance. But in terms of sheer field-busting dominance, Peaty’s wild win over just two lengths of the pool takes the weekend.