Inside the Paris La Défense stadium, Canadian swimmer Finlay Knox stood behind the blocks and felt like he could hear more than 13,000 fans cheering.

Knox, who shared the pool in two races with French swimming sensation Leon Marchand, who won four gold medals and a bronze at the Paris Olympics, estimated the crowd was 10 times louder than usual.

Even though the French fans weren't specifically cheering for Knox, he drew energy from them.

“It was a really incredible moment for me and something I've never experienced in my swimming career,” Knox told reporters Sunday.

The last two Olympic Games took place during the pandemic emergency and Paris marked the return of fans.

The organizers promised a spectacle and so far they have delivered, from the venues to the celebrities in the stands.

Take the women's road cycling event, which Olympic organizers said drew some 400,000 spectators onto the streets.

Even sports in which athletes are accustomed to drawing smaller crowds are noticing a surge in energy.

Canadian tennis player Mo Zhang, who is competing in his fifth Olympics, said it was easier to concentrate in Tokyo without fans. A quiet room makes it easier to hear the competitor hitting the ball.

Even with the added noise, Zhang enjoyed the atmosphere of the southern Paris region, where the table tennis matches were taking place.

“The crowd didn't affect me at all,” he said. “I was just focused on the game.”

A view of the Eiffel Tower

One of France's most famous landmarks, the Grand Palais, was the site of a fencing competition. More than 6,000 fans were able to feel like they were in another era, watching a duel inside the structure built for the Paris Commune Exposition nearly 125 years ago.

Like table tennis players, fencers do not always compete in front of large crowds, but there were many supporters in Paris.

“It’s great to be at the Olympics, no matter what. But fencing at the Grand Palais? It’s the coolest place I’ve ever been,” said Canadian fencer Blake Broszus.

“And seeing how many fans there are here and how excited they are about fencing is something we’re not really used to. So it’s great to come here, feel like a celebrity and do your best.”

Of course, there is no more famous Parisian landmark than the Eiffel Tower. The Tower not only played a starring role in the opening ceremony, but also forms the backdrop for some of the outdoor spaces.

The best view might be from the Eiffel Tower stadium, which was built to host beach volleyball.

The temporary open-air stadium and spectator stands were built so that competitors and fans could have a great view of the Eiffel Tower. More than 11,000 fans can fill the stadium to enjoy both the sport and a spectacular light show at night.

The view of the Eiffel Tower helped the Canadian team of Brandie Wilkerson and Melissa Humana-Paredes win a lucky round game a few days ago after a loss earlier in the day.

“It was very special for a lot of reasons, especially when it's something you visualize,” Wilkerson said.

“It's beautiful, and when you're going through a difficult time and what we've been through just a few hours ago… [before]“It really helps to deepen gratitude for what we're doing here and to be able to show up and appreciate exactly what this moment is.”

Wilkerson and Humana-Paredes will face Spain's Daniela Álvarez and Tania Moreno in the quarterfinals at the Stade de la Tour Eiffel on Wednesday at 11 a.m. ET.

WATCH | Wilkerson, Humana-Paredes advance to quarterfinals after victory over Team USA:

Canada beats USA to advance to Paris 2024 beach volleyball quarterfinals

CBC's Dale Manucdoc and analyst Claire Hanna explain how Canadians Brandi Wilkerson and Melissa Humana-Parades kept Americans Taryn Kloth and Kristen Nuss out of the quarterfinals, and look at what to watch when they face Spain.

Organizers have also held swimming competitions in the Seine and spent $1.5 billion to clean up the long-polluted river. Success has been mixed.

The swimming triathlon took place in the Seine, although the men's triathlon was delayed due to water quality issues. A pre-race training session for the Seine open water marathon swim was also cancelled on Tuesday.

Friendly faces in the stands

The return of fans also marks the return of friends and family, friendly faces in the crowd that were missing at the last two Games in Tokyo and Beijing.

Canadian siblings Gunnar and Isabella Holmgren competed in their first Olympics in cross-country mountain biking.

They ran on a course built on Elancourt hill, the highest point in the Paris region, offering a view of the Eiffel Tower from its summit.

“I think there were about 15,000 people every day. [watching the races] “It's much more than I expected,” said Gunnar Holmgren, who finished 30th in his career.

“The fans were cheering everyone on throughout the race. It was one of the loudest races I’ve ever been to, which is awesome.

His parents, three siblings, and some more distant relatives came to Paris to cheer on Gunnar and Isabella.

“Our family, it's hard to get everyone in one place at one time, just our immediate family,” said Isabella Holmgren, who finished 17th in her event.

Isabella's twin sister Ava also travels the world competing in mountain bike races, just like Isabella and Gunnar.

Another brother, Max, is training to be a police officer, but was able to go watch Isabella and Gunnar compete in the Olympics.

“It definitely made the event really special,” he said.