Every 4 years the sporting world turns to one of the greatest competitions of all time: the Olympics. Held in Rio de Janeiro, Brazil, the 2016 Olympic games is a sure bet to be thrill for everyone watching at home, especially for Americans who are usually the most medaled country to participate.

Of special note in the Olympics this year are a host of returning stars like swimmer Michael Phelps, and track star Justin Gatlin. However, Gatlin will face a tough task against Usain Bolt, largely regarded as one of the greatest sprinters ever. Another familiar face will be women’s beach volleyball star Kerri Walsh Jennings, though she’ll have to compete without her longtime partner, Misty May-Treanor, who retired following their gold medal run in London 2012.

Several other sports stars will also be present, including tennis legends Serena Williams and Novak Djokovic, who are both the top ranked singles players. However, both Roger Federer and Rafael Nadal will not be present.

The basketball tournament will be especially entertaining for Americans, whose teams typically dominate the sport. Names like Kevin Durant, Carmelo Anthony, Klay Thompson, and Kyrie Irving highlight the famous cast, though NBA superstars LeBron James and Steph Curry will not participate.

Soccer will also be a fun event, especially for the host nation, Brazil. With renowned world star Neymar at the helm, the Brazilians will certainly be expecting to win the event. One point of contention is the issue with the Russian team, which has had nearly one third of its athletes banned over doping allegations. It will be sad to see an Olympics without so many competitors from this usually impressive nation, though it’s nice to see the Olympic games committee take such a strong stance against performance enhancing drugs. Either way, it will certainly be a big story heading into the games.

But despite all the big names participating in these games, so much of the fun with the Olympics is in learning about the new athletes in somewhat lesser known sports that rise to greatness and earn a medal. Who will be the surprise star of these 2016 Olympics? We’re about to find out!