Let the countdown to Rio begin.
With 100 days until the opening ceremony in Brazil, TODAY gathered a host of U.S. Olympic stars on Rockefeller Plaza Wednesday as excitement builds for the official start of the Olympics on Aug. 5 in Rio de Janeiro's Maracana Stadium.
Cheers of "U-S-A! U-S-A!" greeted the athletes as they looked ahead to the first Olympics that will ever be held in a South American city. TODAY's Matt Lauer and Savannah Guthrie as well as former TODAY co-anchor Meredith Vieira will host the opening ceremony for the Olympics, which run from Aug. 5-21.
As the buzz continues to build, here are seven reasons to get excited for Rio.
1. Michael Phelps is back.
Just when other Olympic swimmers thought it was safe to go back in the water, the most decorated Olympian of all time with 22 medals, including a record 18 gold medals, is returning for his fourth Olympics.
Phelps, 30, had initially vowed that he was done with Olympic competition after the 2012 Games in London. In a revealing interview with Matt Lauer on TODAY Wednesday, he spoke about checking himself into rehab and his renewed dedication to training for Rio after a difficult time in London.
2. The U.S. women's gymnastics team is set to dominate again.
With a roster that features three-time world all-around champion Simone Biles, 19, and defending Olympic all-around gold medalist Gabby Douglas, 20, the U.S. women's gymnastics team is poised to clean up on the medal stand in Rio.
Biles and Douglas, a pair of P&G athletes, joined TODAY Wednesday to talk about their chances in Rio. Biles has won the last three all-around titles at the World Championships and is on the cusp of being a household name in her first Olympics.
(P&G is a sponsor of TODAY)
Biles' main competition looks to be her own teammate. Douglas is attempting to become the first woman in nearly 50 years to win back-to-back gold medals in the all-around competition.
RELATED: US gymnast Simone Biles poised for stardom at the 2016 Rio Olympics
The two competitors downplayed any rivalry between them.
"We're not catty like that,'' Douglas told Savannah Guthrie.
"(We) keep it fun,'' Biles said.
3. One of the world's fastest women will be attempting a difficult double.
Another P&G athlete, U.S. sprinter Allyson Felix, 30, is attempting to become the first woman to win gold in the 200 and 400-meter races in one Olympics since 1996 and the first American to do it since 1984. The schedule of races was rearranged to allow Felix, the reigning Olympic champion in the 200-meter race and a four-time gold medalist, to attempt the feat.
4. The U.S. women's basketball team will go for a record sixth-straight gold medal.
University of Connecticut coach Geno Auriemma, fresh off leading his Huskies to a fourth-straight national championship, helped unveil this year's Olympic team on Wednesday. Five of his former UConn players are part of the squad, which will be captained by Sue Bird and Tamika Catchings.
5. Ryan Lochte will try to sneak up on the field as an underdog.
Lochte may be an 11-time Olympic medalist, but the champion swimmer believes he will be an underdog heading into Rio thanks to the return of Phelps and the fact that he hasn't "had the best couple of years" in the pool. He played it close to the vest when asked about his goals for this summer.
"I'm going to keep them to myself and keep all you guys guessing,'' he told Matt Lauer.
6. No team will look more stylish at the closing ceremonies than the U.S.
TODAY got a sneak peak at the Olympic closing ceremony uniforms that will be worn by the Americans. Lochte, wrestler Jordan Burroughs and swimmer Haley Anderson showed off the Polo Ralph Lauren outfits in red, white and blue.
7. It will be a three-week beach party on TODAY.
The TODAY set in Rio will be located on the famed Copacabana Beach, where Bob Costas was hanging out on Wednesday to preview the Games. Costas, who will once again be the primetime host of NBC's Olympic coverage, said he has been told it should be "a three-week party."
The Olympic beach volleyball competition will also be held on Copacabana Beach. U.S. competitors Phil Dalhausser and Nick Lucena helped Matt Lauer and Savannah Guthrie brush up on their volleyball skills on Wednesday to get ready for Rio.
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