The United States and basketball, Kenya and steeplechase races, China and table tennis — some countries are synonymous with certain Olympic events. And their dominance is reflected in the medal table year after year.

But the Olympics can be unpredictable, and it's difficult to win the same event every single year. All it takes is one upset, one down year, or one rising international star to end a winning streak. Just ask the 2004 U.S. men's basketball team.

That's why it's so impressive when one country manages to remain unbeaten over the course of multiple decades, and entering this year's Olympic Games, there are some massive streaks from the United States and other nations that will be put to the test in Tokyo.

Below are some of the longest and/or most notable Olympic title streaks currently on the line.

And for more active Olympic streaks, be sure to check out the list of athletes who can three-peat (or four-peat) at the Tokyo Games.

Swimming: Men's 4x100m Medley Relay
9 straight gold medals

Although the U.S. has a number of title streaks on the line, the headliner is its success in the men's 4x100m medley relay for swimming. Team USA has won nine straight golds (dating back to 1984) in this event, but its dominance extends even further than that. Since the medley relay first appeared on the program in 1960, American men have won gold at every Olympics except the boycotted 1980 Moscow Games. All in all, that makes the U.S. 14-for-14 in winning this event at Olympics it has competed in. In Tokyo, however, the U.S. medley team will be without Michael Phelps for the first time since 2000.

Basketball: Women's Tournament
6 straight gold medals

NBA players have turned the U.S. men’s basketball team into a juggernaut ever since they first played at the Olympics in 1992, but a surprise defeat for them at the 2004 Athens Games means that it’s the women who currently hold the more dominant winning streak. In fact, the women’s streak (six) is twice as long as the men’s (three). With WNBA stars like Sue Bird, Diana Taurasi, A’ja Wilson and Breanna Stewart suiting up in Tokyo, the U.S. women’s team will easily be favored to win a seventh straight title.

Swimming: Men's 100m and 200m Backstroke
6 straight gold medals

The U.S. has not lost a men’s backstroke race of any distance since 1992, and five years ago in Rio, Ryan Murphy swept both races to extend that streak. Although he left the 2017 and 2019 World Championships without titles in either event, Murphy will once again be Team USA’s top hope for backstroke gold after sweeping both distances at Olympic Trials. Hunter Armstrong (20, Ohio State University) will also race the 100m in Tokyo, and Bryce Mefford (22, University of California) will join Murphy in the 200m field.

Track & Field: Women's 4x400m Relay
6 straight gold medals

Ever since this event first debuted in 1972, the U.S. women have been on the podium at every Olympics aside from the boycotted 1980 Games. And since 1996, they’ve been unbeatable. Jamaica has consistently been one of their biggest rivals though, and at the last Olympics, the Caribbean nation finished less than half a second behind the U.S. team anchored by Allyson Felix. Felix, now 36, has been part of the last three Olympic relay teams and is eligible to participate again this year after finishing second in the 400m final at U.S. Trials.

Gymnastics: Women's Individual All-Around
4 straight gold medals

Simone Biles will enter the Tokyo Games as the heavy favorite for gold in the all-around competition for women’s gymnastics, which means that the U.S. will be expected to win this event for the fifth consecutive Olympics.

Basketball: Men's Tournament
3 straight gold medals

The U.S. men’s basketball team will be heavy favorites for gold once again this year as they continue to rebuild the winning streak that was interrupted in 2004. Kevin Durant and Draymond Green return to the squad after helping Team USA win gold in 2016. They’ll be joined by other NBA stars including Damian Lillard, Devin Booker, Jayson Tatum and Bradley Beal.

Cycling: Women's Time Trial
3 straight gold medals

Team USA’s last three gold medals in this event have all come courtesy of Kristin Armstrong, and now she’s coaching the woman who could be poised to carry on that legacy: Chloe Dygert. An accomplished rider in both track and road cycling, Dygert became the youngest cyclist (male or female) to win a world title in the road time trial when she did it two years ago at age 22. She suffered a severe leg laceration during a crash at last year’s world championships while trying to defend that title, but recently returned to racing and is expected to be a full-go for Tokyo.

Rowing: Women's Eight
3 straight gold medals

From 2006-2016, the U.S. never lost a major international title in women’s eight, a dominant stretch which included three straight Olympic gold medals. That 11-year winning streak finally came to an end at the 2017 World Championships, but a victory in Tokyo would still give the U.S. the record for most consecutive gold medals in this event. The boat will mostly be filled with Olympic rookies this year. Of the nine women in the boat, only Meghan Musnicki and coxswain Katelin Guregian (née Snyder) are holdovers from the crew that won five years ago at the Rio Games.

Gymnastics: Women’s Team All-Around
2 straight gold medals

The U.S. women have been on the podium for the team event at the last seven Olympics and have come away with gold medals at the last two. With Simone Biles leading the way, the U.S. will be favored to improve that streak and get a third straight win. She’ll be joined by Suni Lee, Jordan Chiles and Grace McCallum on the roster.

Water Polo: Women’s Tournament
2 straight gold medals

The U.S. women’s water polo team has won back-to-back Olympic titles and is in the middle of a historic run overall. They’ve won the last three World Championships (dating back to 2015), the last three World Cups (dating back to 2010), and the last seven World League Super Finals (dating back to 2014). Goalkeeper Ashleigh Johnson and attackers Maggie Steffens and Maddie Musselman are all Olympic veterans and will be counted on for big roles.

Track & Field: Men’s Steeplechase
Kenya
9 straight gold medals

The only active streak that matches Team USA’s dominance in the 4x100 medley swimming relay is Kenya’s streak in men’s steeplechase. Kenya has won gold in the event at nine consecutive Olympics, and on all but two of those occasions (1984, 2016) has had at least two athletes on the podium. The Kenyans also swept the podium on two occasions (1992, 2004). Abraham Kibiwott, Leonard Bett and Benjamin Kigen will be tasked with extending the streak this year after reigning Olympic champion Conseslus Kipruto was left off the team.

Archery: Women’s Team Event
South Korea
8 straight gold medals

The archery team event was introduced to the Olympics in 1988, and every edition of the women’s competition since then has been won by South Korea. The South Koreans are consistently strong in the individual event as well, typically winning multiple medals at each Olympics, including eight of the last nine gold medals. All three archers named to the women’s team — Kang Chae-Young, Jang Min-Hee and An San — will be appearing at their first Olympic Games.

Diving: Women’s Springboard
China
8 straight gold medals

The diving events at the last Olympics were again dominated by China, which took home seven of the eight gold medals, and that’s likely to be the case once more in Tokyo. But there’s one particular event in which the country has built up a massive winning streak: women’s individual springboard. Chinese divers have won gold in this event at the last eight Olympics (dating back to 1988) and earned a second medal (either silver or bronze) at the last five Olympics. Reigning Olympic champion Shi Tingmao is unbeaten in major international competitions since 2013 and will be favored to extend this streak.

Table Tennis: Women’s Singles
China
8 straight gold medals

Another sport that China dominates is table tennis. Since it was introduced in 1988, the country has won all eight gold medals (plus nine medals of other colors) in women’s singles. This year’s team will feature world No. 1 Chen Meng, world No. 3 Sun Yingsha and reigning world champion Liu Shiwen vying for the country’s ninth straight title. In a testament to how difficult it is just to make the Chinese team, reigning Olympic champion and 2012 silver medalist Ding Ning was left off the roster despite being ranked No. 5 in the world.