RIO DE JANEIRO — When Michael Phelps lifts the American flag to lead the United States team into the Olympics on Friday, he’ll help kick off a 16-day athletic competition that organizers hope will wipe away more than a year of public concern over the Zika virus, security, doping and the host city’s economic instability.

Phelps, swimming in his fifth Olympics and already the most prolific medal winner in history, is among a group of American stars who are likely to command international headlines and dominate NBC’s 2,084 hours of coverage over 11 networks.

They include familiar faces such as Katie Ledecky, already the best female swimmer in the world at age 19, and Carmelo Anthony, who is seeking his third gold medal in men’s basketball.

There will also be new American stars such as Simone Biles, who’s expected to bring a dazzling degree of difficulty to women’s gymnastics.

“My emotion is going to be 10 times what it’s ever been,” said Phelps, who didn’t walk in an opening ceremony at his previous four Olympics.

Olympic officials certainly hope the athletes will overshadow the difficulties and controversies that have marred the build-up.

“I think we’re all looking forward to (Friday’s) opening ceremony, then finally the athletes and the sport are taking over,” said Thomas Bach, president of the International Olympic Committee. “We also had to address some last-minute challenges as is normal just before an Olympic Games. But I have to say the cooperation with the organizing committee and the city is going very, very well.

“Therefore, I’m very confident these issues will be addressed and then we’ll have a really great Olympic Games here in Rio de Janeiro.”

More than any athlete, Rio itself has been the main character in the run-up to these Olympics.

It’s a city of lush green hills and stunning ocean views, but also of traffic-choked roads and cramped favelas plagued by some of the worst poverty in the world. The famed Art-Deco statue of Christ the Redeemer looks down from its perch in Tijuca Forest National Park, but on the ground, a different sort of art – graffiti – covers many surfaces, from the inside walls of highway tunnels to the facade of an abandoned church.

Bach called the myriad troubles a “stress test I hope we will not have to withstand in the future.”

“There were health challenges, environmental challenges, wherever you look, there were huge, huge challenges, if not a deep crisis,” the IOC president said. “Nevertheless, you see this country, this city, this organizing committee has managed to transform a city and put an Olympic Games on stage.”

Aside from questions about Rio, the specter of doping also has hovered over these Olympics, with more than 100 Russian athletes banned because of alleged state-sponsored drug use and 271 didn’t receive approval to compete from the International Olympic Committee until Thursday.

Phelps is among the athletes who expressed frustration with a perceived lack of enforcement.

“It’s very concerning to me that our governing bodies have dropped the ball in many ways on this,” said his longtime coach, Bob Bowman, who’s also head of the U.S. men’s swimming team. “The system is broken and it has to be fixed.”

And yet the show is set to go on Friday night.