Splashing water and submerged cheers provided the soundtrack to the first week of the Tokyo Olympics. Before attention turned to the athletics track at National Stadium, events inside the Tokyo Aquatics Centre served as the steady backdrop to the Summer Games, a wellspring of excitement even as viewers were regaled by the close combat of fencing, judo, and taekwondo and first-time sports such as surfing and skateboarding.

For the first time in more than twenty years, an Olympic swimming meet was not graced by the presence of Michael Phelps, who over the course of five consecutive Games emerged as the greatest ever Olympian. Still there was no shortage of star power in the pool, with world record holders Caeleb Dressel, Katie Ledecky, Kristóf Milák, and Adam Peaty hoping to make history and in some cases retain their Olympic titles.

American exceptionalism in the swimming pool led to a change of schedule, as the television network NBC used some of its considerable leverage to switch the medal events to the morning session for the sake of prime time broadcasting. The swimmers took a while to adjust, but by the end of the week some fast times were accompanying the flow of bronze, silver, and gold medals. Here are seven of the most memorable firsts from the swimming meet at the Tokyo Olympics.

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Ahmed Hafnaoui Prompts Wild Celebrations in Tunisia

The slowest of the qualifiers for the men’s 400 metre freestyle final, Ahmed Hafnaoui was a rank outsider away from the thrust of the action in lane eight. Despite maintaining second position for much of the race, the Tunisian was so unfancied that even heading into the last lap, most pundits still wondered whether he could manage to hold on for a medal.

Instead Hafnaoui stretched past the pre-race favourite Jack McLoughlin to touch the wall in first place, becoming only the second Tunisian to win gold in the pool, following in the armstrokes of Oussama Mellouli. Hafnaoui was already the first big underdog story of the Olympic Games, but when footage emerged of his family wildly cheering him on from back home in Tunisia, his victory in the pool transcended the sport and became a pop-cultural moment.

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Adam Peaty Starts the Gold Rush for Great Britain

Beyond his bulging chest and imperious swagger, Adam Peaty’s domination of the 100 metre breaststroke shows in the facts as well as the figures. The reigning Olympic champion heading into Tokyo, Peaty could boast the sixteen fastest times ever over the distance and remained a firm favourite for the gold medal. The heats brought the flicker of a challenge from Arno Kamminga, who earlier this year became only the second man to go under 58 seconds. But in the final of the men’s 100 metre breaststroke, the Dutchman was delighted with second place as Peaty once more stormed to victory.

In the process Peaty became the first British swimmer to retain an Olympic title. His success started the gold rush for Great Britain, as over the next few hours Tom Pidcock won gold in the cross country mountain biking while Tom Daley and Matty Lee added gold in the men’s 10 metre synchronised platform diving. Peaty led the British swimming team to their best ever showing at an Olympics, with four golds and eight medals in total, as Duncan Scott became the first British Olympian to win four medals in a single Games.

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Lydia Jacoby Takes Gold Home to Alaska

In the small town of Seward where Lydia Jacoby grew up, the locals would regale tourists with fanciful tales of the teenage swimming prodigy who trained with whales and sea lions. A steadfast member of the Seward Tsunami Swim Club, at just 17 years of age Jacoby made her way through the American trials to become the first swimmer from Alaska in the history of the Olympics.

Already boasting a national age group record in the event, in the women’s 100 metre breaststroke final in Tokyo the youngster had to contend with two established stars of the sport in the South African Tatjana Schoenmaker and her feisty American counterpart Lilly King. From lane three, it was Jacoby who sprung the surprise victory, leaving Schoenmaker and King to silver and bronze as gold became the colour of Alaska’s first ever Olympic swimming medal.

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Equality Goes the Distance at the Tokyo Olympics

With equality the order of the day, the Tokyo Olympics introduced three new events to the swimming meet. The 1500 metre freestyle had remained the preserve of men ever since its debut back in 1908 at the inaugural Olympic pool meet, while the 800 metre freestyle was added for women in 1968. Finally in Tokyo the disparity was corrected, as both genders gained the opportunity to race over the two distance events.

If Katie Ledecky was still reeling from her first ever Olympic defeat, she rebounded in the first ever women’s 1500 metre freestyle final. Ledecky was edged into silver over 400 metres by the impressive Australian Ariarne Titmus, but came back strong in the distance events to add two more gold medals to an already historic tally. Meanwhile her American compatriot Robert Finke was also in the midst of an Olympic distance double, as he secured gold in the first men’s 800 metre freestyle final.

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Tatjana Schoenmaker Smashes the 200 Metre Breaststroke Record

After losing out to Lydia Jacoby in the 100 metre breaststroke final, Tatjana Schoenmaker had a point to prove over 200 metres. In the final of the event she again faced off against Lilly King, as the former 100 metre Olympic breaststroke champion continues to grow in strength over the longer distance.

Schoenmaker was pushed hard over the first three laps, before pulling away to take gold and set a new landmark in women’s breaststroke swimming. The South African had succeeded in setting the first individual world record of the Tokyo Games, with her time of 2:18.95 making her the first woman in history to complete the race in under 2 minutes and 19 seconds. Largely confined to the relay events, the only other individual world record to fall in the pool came courtesy of Caeleb Dressel in the men’s 100 metre butterfly final.

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Swimming Embraces the Vogue for Mixed Relay Events

Mixed relay events were the new vogue at the Tokyo Olympics. While the mixed 4 x 400 metre relay caused some consternation out on the track, and an action-packed mixed relay triathlon saw teams take turns over condensed courses of swimming, cycling, and running, the pool inside the Tokyo Aquatics Centre played host to a boisterous 4 x 100 metre medley relay.

This was the first ever mixed-gender swimming event at an Olympic Games, and the final was won in world record time by the British team of Kathleen Dawson, Adam Peaty, James Guy, and Anna Hopkin. While most teams used male swimmers on the middle breaststroke and butterfly legs, leaving women to bring things home with a flourish in the freestyle, the United States erred badly in the middle of the race, and were left languishing in fifth despite the last-ditch heroics of Caeleb Dressel.

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Emma McKeon Becomes the Greatest Australian Olympian

Gold in the 50 metre freestyle, the 100 metre freestyle, and the 4 x 100 metre freestyle relay plus a couple of bronze medals had already made Emma McKeon the most decorated Australian of all time, but it took the penultimate event of the swimming meet in Tokyo to confirm her status as the greatest ever Australian Olympian.

In the women’s 4 x 100 metre medley relay, McKeon swam the butterfly leg after Kaylee McKeown and Chelsea Hodges had carried the Australians out, and before Cate Campbell swept the team to gold marginally ahead of the United States, scoring new Olympic and Oceanian records. The win gave McKeon her seventh medal of the Tokyo Games, including four golds, and her eleventh Olympic medal in total. The tally puts her two ahead of the next best Australian athlete Ian Thorpe, who also laid claim to five golds while settling for three silver and one bronze. With the next Olympics just three years away, McKeon could well add to her legacy in Paris.