Olympic Channel were on site in Korea as Adam Peaty broke the 100m breaststroke world record on the first day of swimming competition at the World Championships.
Olympic Channel are on site at the FINA World Championships in Gwangju, South Korea.
Swimming competitions finally began on Sunday 21 July. Olympic champion Adam Peaty broke his own men's 100m breaststroke world record, becoming the first man to swim under 57 seconds in the discipline.
You can re-live all of Sunday's action with our blog below (newest updates first). Come back for daily live blogs throughout the Championships. Alternatively, you can catch up with what happened on Saturday 20 July here.
12 - 28 Jul 2019
FINA World Championships - Gwangju
All times below are Korean Standard Time (UTC+9 hours).
Well. That was quite a way to start the swimming competition at these World Championships.
Congratulations to Adam Peaty on his stunning world record, as well as to the medallists in today's four finals.
Racing continues tomorrow with four more finals, as well as the start of the high diving events.
We leave you with a gallery of today's swimming action. See you tomorrow.
It was a rare loss for Katie Ledecky today in the women's 400m freestyle. It was just the second time she has been beaten in a World Championships final, after the 200m freestyle defeat to Federica Pellegrini in 2017.
"I just got to the last turn and felt like I just tightened up, my legs were just dead and obviously Ariarne took advantage of that and had a heck of a swim," she said.
"Obviously this stings a little, it's unfamiliar and different, and I need to rebound from this and get my fight back.
"I felt like I stayed pretty calm throughout the race, felt like I made a move at the right time, but my legs and arms didn't have it at the end. Just have to move on and focus on the next races.
"Tonight I felt great, honestly my physical preparation has been great for this meet and I really expected to be a lot faster than that. I haven't looked at the splits yet, haven't really analysed the race a lot yet. I don't think I over-swam the first half. I'll just have to analyse."
The five-time Olympic champion also congratulated her opponent on the win.
"The swims that she's gone under four minutes, she always goes out fast, so I knew she'd be right with me or we'd be right together probably through 200. Felt like I tried to make a move and got a little ahead, and obviously she stayed right with me and was ready to be there if I fell off, and unfortunately today that happened.
"I've only raced somebody that's gone under four minutes two or three times in her, so it's an unfamiliar race for me. It's something that I can't replicate back home when I swim meets. Obviously, she can't really either, so that's no excuse, it's something I need to prepare for and put myself in those racing situations whatever way I can.
"I was nervous for it, I knew it was going to be a tough race just like any other race here, and it just didn't go my way today.
"I'm prepared to swim fast at this meet, tonight just wasn't meant to be. There are no physical issues."
Here's what Caeleb Dressel had to say in the mix zone after USA's men's 4×100m freestyle relay victory, their first gold of the Championships.
"The relay was great. All the guys stood out, especially Zach (Apple), 46.8 on the split, and then Nathan (Adrian) just does his job every single time.
"It's just experience, you can't beat experience. So he did great, a tough leg anchoring that with the Russians coming on quick.
"I'm very happy with day one."
Cate Campbell, one quarter of Australia's winning women's 4×100m freestyle relay team, was understandably upbeat as she spoke to journalists after her medal ceremony.
"It was a great night in the pool by the Australians, we medalled in every event tonight, so really pleased across the board," she said.
"We knew coming into the race that it was going to be a very tough race tonight, and the girls held it together to get the win."
On Ariarne Titmus' triumph over Ledecky, she added: "I think the entire warm-up pool stopped to watch that last 50, and when we watched her in the last 25 swim away from Ledecky, there was a resounding 'woah'.
"The people who weren't stopped made sure they put up their head to see what was going on. It was such a mature swim and incredibly inspirational."
She shocked Katie Ledecky in the women's 400m freestyle final, but Australian Ariarne Titmus shows no signs of being fazed by it.
"I feel pretty normal. It was just a swimming race," she said.
"My coach said before the race there's three outcomes: 'You could swim great, you could swim good, you could swim bad. You'll still wake up tomorrow.' There was no pressure for me coming into this race, but I just wanted to come in and fight as hard as I could. That last 50, I gave it everything, and I'm really happy.
"I knew I had to take it out hard to be with her. Her third 100 is still a lot better than mine, and I saw her move, and I thought to myself 'just hang in there, she's going to have more and you're not going to get her', but suddenly I just felt something and it's very good."
And Titmus knows her rival will come back stronger. "She's the greatest ever, so this isn't going to bother her. Next year I know there's going to be a real battle."
The only man to swim under 58 seconds, and now under 57 seconds in the 100m breaststroke, Adam Peaty, sounds pretty overwhelmed with his time of 56.88 in the semi-finals.
"I don't know, there's no real word, except for incredible," he said.
"Obviously I've been chasing that for years now. As soon as I touched that wall in Rio, I was like, 'I could go faster'. It's a very special journey that we've had and hopefully we'll go a lot faster tomorrow.
"I said to all these guys down there, it's still a semi-final. It would be a bit embarrassing to go world record and then not come away with a world title.
"I don't think like that. What the process in my head is that tomorrow anyone can still beat me, I can beat anyone.
"Going into that race tomorrow as the world record holder, I want to achieve the best possible version of myself. I'm just going to enjoy it. It was a great race."
Australia's Olympic champion Mack Horton, who is coming back from some time off, has been reacting to the 400m freestyle result.
"I'm happy to be getting closer to my Rio time," he told journalists in the mix zone. "To be honest I thought I had a bit more in me. My strength has always been the back end, so I probably need to enhance the strength, so obviously just need to work on the weakness which is the front end as well."
On gold medallist Sun Yang, who is currently facing a case brought by the World Anti-Doping Agency at the Court of Arbitration for Sport, Horton said: "My overriding emotion is probably frustration. I think you know what the rivalry is like. I don't think I need to say anything, I think his actions and how it's been handled speaks louder than anything I'll ever say."
At the medal ceremony, Horton refused to shake hands with Sun, and did not pose for photos with Sun and bronze medallist Gabriele Detti of Italy. The Australian opted to step off the podium and stand behind it after the Chinese anthem was played while Sun and Detti posed on the top step. Horton posed for photos with Detti separately during the lap of honour.
Sun declined to do interviews in English after the race.
World record holders Australia set a new championship record in the women's 4×100m freestyle relay.
3:30.21 is just 0.16 seconds behind their world record.
That was a very tight fight between them, Canada, and USA, who win silver and bronze respectively.
It's a new Championship record in the men's 4×100m freestyle relay for the United States! 3:09.06 the winning time.
They were pushed all the way by Russia, who were only a metre or so behind at the finish.
Bronze to Australia.
Nathan Adrian, who is competing after cancer treatment, swam the anchor leg for the world champions.
Katie Ledecky still looks somewhat surprised that she lost that final as the medallists come out for the medal ceremony.
Ariarne Titmus grins from ear to ear as Advance Australia Fair sounds for her victory.
Katinka Hosszu, the Olympic champion and world record holder, wins her 200m individual medley semi-final by nearly two seconds. She didn't really push, either: she was over a second off her world record time.
Sydney Pickrem won the first heat, but still over a second and a half behind Hosszu's time.
China's Yan Zibei clocks 58.67 to set a new Asian record on his way to winning the first men's 100m breaststroke semi-final.
But the big man, Britain's Olympic champion Adam Peaty, is up for the second semi. He's aiming for a sub-57s time: his world record is 57.10.
Under the WR split! This is going to be it! YES! 56.88 seconds!
He's in a league of his own. No one else has even broken the sub-58-second barrier.
It's close! Katie Ledecky is being caught! On the final lap! She's been beaten!
Ariarne Titmus of Australia has beaten Ledecky! It's a new Oceania record. 3:58.76.
USA's Leah Smith took bronze, but what a finish!
World record holder Andrii Govorov of Ukraine easily wins the first semi-final in the Men's 50m butterfly, in 22.80 seconds.
A new Championship Record for Caeleb Dressel in the second semi! 22.57 seconds to take 0.1 second off Milorad Cavic's time from 2009. Only 0.3 seconds away from the world record.
That second semi-final was quick. Dressel and Govorov are joined in the final by Nicholas Santos, Oleg Kostin, Michael Andrew, Szebasztian Szabo, defending champion Ben Proud, and Andrey Zhilkin.
We've just had the two semi-finals in the Women's 100m butterfly.
The eight finalists in tomorrow's medal race are: Sarah Sjostrom, Margaret MacNeil, Marie Wattel, Emma McKeon, Brianna Throssell, Elena di Liddo, Kelsi Dahlia, and Louise Hansson.
Sjostrom won that second heat fairly comfortably, but just 0.01 seconds separated Wattel and McKeon in the first semi.
China's Sun becomes the third man to win an event four times in a row at the Worlds, taking gold ahead of Horton of Australia and Detti of Italy.
The others to do it were Grant Hackett (1500m free) and Ryan Lochte (200m IM).
The first final is underway! The other finalists are Marco de Tullio (Italy), Jack McLoughlin (Australia), Danas Rapsus (Lithuania), Gabriele Detti (Italy), Zane Grothe (USA), and Jin Xinjie (China).
The evening session of swimming is starting in 10 minutes and first up it's the much-anticipated clash between Olympic champions Sun Yang and Mack Horton in the Men's 400m Freestyle.
Safe to say we're just a little bit excited!
Germany really hit their straps to run out 25-5 winners over South Africa in the men's water polo competition.
That means Tuesday's quarter-finals will be contested between Olympic champs Serbia, world champs Croatia, Hungary, Australia, Italy, Greece, Serbia, Spain, and Germany!
Ten years after each city hosted the 16th and 17th World Championships respectively, FINA will return to the Russian and Hungarian cities.
Not one for the faint hearted, the high diving starts tomorrow.
We will be on site for the afternoon session, let's hope this storm stays away!
Well, at the moment the answer to the last question looks like Germany will face Croatia in the quarter-finals.
With around two minutes left in the second quarter, South Africa trail by seven goals, 9-2.
So, Spain triumphed over Japan in the end, winning 15-7, to reach the quarter-finals.
Who will join Hungary, Australia, Italy, Greece, Serbia, Spain, and Croatia in the last eight?
In 15 minutes, we will see the final cross-over match between South Africa and Germany.
Just behind the water polo arena, a strip of authentic Korean food carts has been set up, selling everything from spicy chicken to kimchi and bulgogi (marinated barbecue beef).
There's a large grassy area with tables, beer stalls and even a stage for musical performances set up so there's something for everyone there.
Spain and Japan are duking it out in the third of four cross-over matches today.
Australia and Greece have already made it through to the quarter-finals, and Spain look more likely to join them at the moment.
At half-time in this playoff, the Europeans lead 5-4.
The Greek men's team have defeated USA 11-9 in their cross-over match and will now contest the quarter-finals.
It was a close game in which the USA took the first quarter, but that seemed to kick the Europeans into life, who found their form in the nick of time.
China's Sun Yang can become the first person to win the Men's 400m Freestyle four times. He currently shares the record for three wins with Australian Ian Thorpe.
Five-time Olympic champion Katie Ledecky can become the third woman to win four world titles in a specific individual event. Katinka Hosszú, who competes in the 200 IM final this evening, has won four 400m individual medley and Sarah Sjöström has four wins in the 100m butterfly.
Nathan Adrian, who was diagnosed with cancer at the start of the year, can win a record-equalling third World Champs gold in the men's 4x100m freestyle relay.
Australia come from behind to pip Montenegro 13-11 in a water polo men's cross-over thriller!
The victory means the men from Down Under progress to the quarter-finals.
The locals have really gotten into the sport here this week, and as we head into the elimination games, we're getting big crowds now!
The Swedish sensation breezed through qualifying in the 100m Butterfly this morning to continue her amazing form this year.
She was mobbed outside the stadium after, but fans will get to see her again in this evening's semi-finals.
While only the top eight teams in the heats for each 4×100m freestyle relay event made the final, there was still good news for some of those who didn't make it.
In addition to the eight teams in the final, the following countries also clocked a time fast enough to qualify for Tokyo 2020:
Women's 4×100m freestyle relay: Russia; Hong Kong, China; Czech Republic; Poland
Men's 4×100m freestyle relay: Japan; Greece; Germany; Poland
USA place a huge importance on relay races, and they will be pleased with winning their heat in Gwangju.
The United States recorded the fastest time in qualifying of 3:11.31.
Olympic champions Australia justified their favourites tag in the 4x100m Freestyle relay.
Spearheaded by the Olympic champion Campbell sisters, the women in yellow won Heat 2 in the fastest qualifying time of 3:33:39. Their world record effort from Rio 2016 is below.
Canada finished second, Sweden third, Heat 1 winners USA in fourth, and will all meet again in this evening's final.
There's no such thing as a warm-up for 100m Butterfly world record holder Adam Peaty.
In the final heat the Brit blasted through the water in 57.59 seconds to take top spot by over a second, heading into this evening's semis.
His time on the big screen got the biggest cheer of the morning so far.
That looked too easy.
The final heat of Women's 400 Free goes to Katie Ledecky in 4:01.84 - the morning's top time.
Australia's Ariarne Titmus finished second overall with Hungarian Ajna Kesely third.
The top eight qualify straight through to this evening's final.
Caleb Dressel has sown up first place in the Men's 50m Butterfly heats in 22.84 seconds, but he's not alone.
To everyone's amazement, Ukraine's Andrii Govorov equaled the American's time in his heat to also qualify for the semis in top spot.
Dressel's compatriot Michael Andrew also qualified, taking his heat in 23.09. However there was disappointment in that race for Rio 2016 100m Butterfly Olympic gold medallist Joseph Schooling, who crashed out in seventh position.
Defending world champion Ben Proud didn't have his best race in the final heat, but the Brit also qualifies for the semis.
Unsurprisingly, Sweden's Sarah Sjostrom eases to victory in 56.45.
She never gave up the lead and that's the fastest time in qualifying.
Australia's Emma McKeon and Canadian Margaret MacNeil 57.10 are second and third respectively.
The semi-finals take place this evening.
Roared on by a passionate Chinese fan base, Sun Yang sets the fastest time in 400m Freestyle qualifying in 3:44:10.
Joining Sun in this evening's final will be 400m Free Olympic champion and his fierce rival Mack Horton from Australia. What a final that will be!
The Hungarian fans voice their approval as 200m Individual Medley Olympic champion Katinka Hosszu comes from behind to win her heat comfortably.
The Iron Lady is through to tomorrow's final in a time of 2:07:02.
China's Ye Shiwen was second.
In the final 200 IM heat, Spain's 200m Butterly Olympic champion Mireia Belmonte finishes seventh and will go no further in this event.
The five-time Olympic champion will compete in the 400m Freestyle heats this morning,
The American could win her 15th world title today. Only Michael Phelps (26) and Ryan Lochte (18) have won more.
But what is her biggest challenge to overcome? Click here to find out.
We are 10 minutes out from the first swimming events. Get your snacks ready, strap in and let's go!
A quick shout out to the pink-shirted volunteers who, come rain or shine, are always on hand to help out with a smile. The epitome of Korean hospitality.
Thank you all!
When the likes of Olympic gold medallists Katie Ledecky, Caleb Dressel and Sarah Sjostrom arrive in town, it's difficult not to get excited.
There's been a change of atmosphere as the athlete and media villages alike start to pack out, and you can read all about it below.
10:00 - 13:45 Swimming preliminary rounds
Women's 100m Butterfly
Men's 400m Freestyle
Women's 200m Individual Medley
Men's 50m Butterfly
Women's 400m Freestyle
Men's 100m Breaststroke
Women's 4x100m Freestyle Relay
Men's 4x100m Freestyle Relay
10.30 - 13:30 Water polo: Men's crossover matches
20:00 - 22:15 Swimming
Men's 400m Freestyle final
Women's 200m IM semi-final
Men's 50m Butterfly semi-final
Women's 400m Freestyle final
Men's 100m Breastroke semi-final
Women's 100m Butterfly semi-final
Men's 4x100m Freestyle Relay final
Women's 4x100m Freestyle Relay final
Gooood morning and welcome back to the Olympic Channel daily blog.
It feels like Christmas morning here in Gwangju as today marks the first day of swimming competition at the 2019 FINA World Championships!
It matters not that it's already bucketing down with rain outside, as we will be inside in the spectacular Nambu University Aquatics Centre to bring you all the latest news.
We have four swimming medal finals to bring you today.