Biles seeks more Olympic gymnastics glory as athletics kicks off in Paris
A total of 16 golds were up for grabs on the sixth full day of competition in Paris, where torrential early rain forced a half-hour postponement to the start of the men's walk.
But the skies cleared as the athletes took to the course - a stunning loop crossing the River Seine in front of the Eiffel Tower.
US star Biles steps back into the spotlight seeking to become the first woman ever to regain the Olympic all-around title after she famously withdrew in Tokyo with the debilitating "Twisties".
The 27-year-old returned to the top of the podium on Tuesday with team gold, her eighth Olympic medal, five of them gold, to become the most decorated US Olympic gymnast.
Biles, the reigning world champion, wants to do it in style with a new skill on uneven bars that would be the sixth unique skill named after her.
But Biles faces a stern challenge from teammate Sunisa Lee, reigning Olympic all-around champion, who is on a comeback trail every bit as compelling as her compatriot.
Lee was diagnosed with two undisclosed kidney conditions in early 2023. However, she declared herself "in remission" in April and counts herself stronger than she was in Tokyo.
Another top contender is Brazil's Rebeca Andrade, who said it was an honour just to compete against Biles.
"She's a reference, a role model for the whole world, gymnastics and athletes alike to see how happy she is to compete. That's what's sport is all about," said Andrade.
'Red hot form'
Meanwhile, the men's and women's 20km walk races launched the athletics programme.
Italy's Massimo Stano was bidding to become the first man to win back-to-back gold in the event after triumphing in Tokyo but he was beaten into an agonising fourth, with Brian Pintado from Ecuador taking gold.
It was Ecuador's second Olympic title in the event, Jefferson Perez taking gold in 1996.
In the women's race, Stano's compatriot Antonella Palmisano was also defending her Olympic title in Paris.
Another packed schedule in the pool includes the women's 200m butterfly final, featuring 17-year-old Canadian prodigy Summer McIntosh, fast becoming one of the stars of the Games.
Already 400m medley champion and 400m freestyle runner-up, McIntosh faces a stacked field including defending champion Zhang Yufei from China.
The 200m women's breaststroke stars South Africa's Tatjana Smith, aiming to become the first woman to do the double since compatriot Penny Heyns at Atlanta 1996.
Smith won Tokyo 200m gold in a world record 2:18.95 and is in red-hot form after securing the 100m title on Monday.
Fresh from winning double gold in a sensational night in the pool on Wednesday, home hero Leon Marchand also swims again in the 200m individual medley.
Other golds up for grabs include kayak canoeing, fencing, judo, rowing, sailing, shooting.
Golf teed off with eight of the world's top 10 competing, including two-time major champion Collin Morikawa and the world's top-ranked player Scottie Scheffler.
