He's the greatest Olympian ever, with a staggering haul of 22 medals - 18 of them gold - since first testing the water in Sydney as a teenager in 2000. Now Michael Phelps is a 31-year-old new father trying to cap off a remarkable career with one final gold rush in Rio. He has qualified for three individual races but also could swim in up to three relays.
After coming out of a brief retirement and coming to terms with some personal issues, he'll be the titular leader of a U.S. team loaded with both proven talent and young swimmers hoping to make a splash.
Among them is Ryan Lochte, who has 11 medals of his own and will try to go out on top in his rivalry with Phelps in their showdown in the 200-meter individual medley.
"I don't know of another person in this world who brings out the best in me like he does," Phelps said. "Neither one of us likes to lose."
Neither does Katie Ledecky, perhaps the most dominant swimmer in the world. She will be a big favorite to add to her medals from the London Olympics, where she surprised everyone by winning the 800 freestyle as a 15-year-old.
All eyes won't be on the water in Rio. On land, Jamaica's Usain Bolt figures to electrify fans as he did in the last two Olympics, where he dominated the sprints. With Russia's track team banned because of doping allegations, some surprise winners also are likely.
Fears of Zika, polluted water and crime aside, the Rio games have a lot to offer. The scenery will look spectacular on TV, and athletes will compete for glory under the kind of stifling pressure that only the world's biggest sporting event can impose.
There will be tears and cheers, surprise winners and devastated losers. New stars will be born, and old ones will take one last shot at gold when the games begin Aug. 5.
The biggest star, though, is Phelps, who insists this will be his last time, more eager than he was four years ago in London and more secure in who he is now with an infant son and more settled personal life.
This time, he's not going to waver. There will be no more swimming after these games, no dreams of taking yet another shot at the age of 35 in Tokyo
"I'm done," Phelps said. "The body is done. This is my last one."
Other things to watch for in Rio: NEW SPORTS
Golf returns to the Olympics for the first time in 112 years, while rugby also makes a return of sorts with the rugby sevens competition. Golf will be without some of the world's top male players, who withdrew either because of Zika worries or scheduling conflicts, but a full field is set anyway for both the women's and men's events. Watch for Fiji, a favorite in men's rugby, to win the country's first-ever Olympic medal.
GYM GEMS
They call Aly Raisman "Grandma" because at 22 she's pushing traditional age limits for gymnasts. But the captain of the "Fierce Five" U.S. women's team that won gold in London will be back, as will reigning all-around champion Gabby Douglas. The best member of the strong U.S. team, though, is Simone Biles, a 4-foot-9 bundle of moves who has not lost a major competition since 2013 and is the three-time reigning world all-around champion.
HOOPS
No Kobe. No LeBron. No problem. The U.S. men's basketball team is still a prohibitive favorite to win gold yet again, despite the absence of some stars of Olympics past. With Kobe Bryant retired and LeBron James resting after winning the NBA title, the roster is missing some star power. But Kevin Durant will be in Rio, and so will Klay Thompson. Carmelo Anthony is in, too, as is Kyrie Irving. Spain, France and Brazil should fight for the silver and bronze.
TUNING IN
Need a quick Olympic fix at any time of the day? No problem. Broadcasters around the world are showing the games, but NBC is going all out to make sure the Olympics are a big part of everyone's summer. Besides coverage on NBC's assortment of stations, a whopping 4,500 hours of Olympic action will be available for live streaming on everything from phones to TV sets. Expect to see lots of swimming and gymnastics, but plenty of hours dedicated to even the most minor sports and 170 commentators to tell you all about it.