Images from Monday's swimming action at Paris La Defense Arena, Nanterre, France.
Canada declared Summer time in the Paris Olympic pool on Monday and the country's 17-year-old sensation Summer McIntosh made it look easy while others celebrated medals won by barely a fingertip.
The world record holder blew away her four-stroke rivals to win the women's 400 metres individual medley (IM) gold and add a second medal to her haul after Sunday's silver in the 400 freestyle.
"It's Summer Time for Canada," declared one poolside banner at the La Defense Arena and it was no more than a statement of fact.
McIntosh touched the wall a full 5.69 seconds clear of American Katie Grimes, with Emma Weyant taking bronze for the United States.
Canada's first gold of the meet was followed in short order by Romania and South Africa's first, with David Popovici winning the men's 200 freestyle and Tatjana Smith the women's 100 breaststroke.
Australia stayed top of the swimming medals table with three golds, to two for the United States, after red-headed rocket Mollie O'Callaghan beat defending champion and teammate Ariarne Titmus to the women's 200 metres freestyle title in Olympic record time.
O'Callaghan wins 200m freestyle with Olympic mark
Australia's red-headed rocket Mollie O'Callaghan upset teammate and defending champion Ariarne Titmus to win gold in the women's 200 metres freestyle at the Olympics on Monday.
O'Callaghan stopped the clock in an Olympic record 1:53.27 at La Defense Arena, 0.54 seconds ahead of Titmus, with Hong Kong's Siobhan Haughey taking bronze.
Only weeks after Titmus swiped her World record at Olympic trials, O'Callaghan turned the tables on her clubmate with a sizzling final lap.
She also foiled Titmus's bid to become the first swimmer to successfully defend a 200 metres freestyle Olympic gold.
Popovici takes men's 200m Freestyle gold
Romania's David Popovici beat Britain's Matt Richards by 0.02 of a second to win the men's 200 metres freestyle gold.
Luke Hobson of the United States took the bronze.
Popovici won in a time of one minute 44.72 seconds after being behind until the final 50.
Reigning Olympic champion Tom Dean failed to qualify for the event after finishing third at the British trials in April behind Richards and Duncan Scott.
Tatjana wins 100 metres Breaststroke gold
Tatjana Smith took South Africa's first gold of the Paris Olympics added the 100 metres breaststroke title to the 200 metres she won at Tokyo 2021 under her maiden name of Schoenmaker.
China's World champion Tang Qianting took the silver medal and Ireland's Mona McSharry shed tears of joy and amazement after an extraordinary three-way battle for bronze.
Tang led at the turn but Smith, only fourth at that point, powered back to win in one minute 05.28 seconds, 0.26 clear of the Chinese, to make up for securing silver in the event in Tokyo.
The winning time was slower than the 1:05.00 Smith had clocked in the heats.
McSharry touched out third by the very slimmest of margins, beating Italy's Benedetta Pilato and world record holder and 2016 champion Lilly King of the United States both by 0.01 of a second.
The 23-year-old's medal was Ireland's first of the Games and there were plenty of her supporters in the stands.
Italy's Ceccon wins men's 100 metres Backstroke
World record holder Thomas Ceccon of Italy made a thrilling late surge to claim the men's 100 metres backstroke gold at the Paris Olympics on Monday.
The former world champion touched the wall in exactly 52 seconds, edging China's silver medallist Xu Jiayu by 0.32 of a second at La Defense Arena.
American Ryan Murphy took bronze and was brave in his bid for a second Olympic gold in the event, eight years after being champion at the 2016 Rio Games.
Xu led for most of the race but Ceccon found another gear to condemn the veteran Chinese swimmer to a second 100m backstroke silver, eight years after he finished runner-up to Murphy.
For the rangy Ceccon, it was confirmation of his talent since announcing himself with the world record in 2022 and claiming the world title in Budapest that year.
