Any major event in the world has its biggest stars. And the upcoming Olympics in Rio de Janeiro are no exception. The total number of athletes who will participate is likely to cross 10,000, but these are some of the leading lights you should definitely keep your eyes on.

1. Usain Bolt: Jamaica

His Last Bow. This might be the title of a Sherlock Holmes classic, but it also encapsulates what the Rio Olympics means to the Jamaican sprinter, easily among the greatest and most recognised athletes of his generation.

The champion sprinter has already announced that he will retire after Rio 2016, though he has hinted he could reconsider. In any case, the 11-time world title holder, gold medallist and world record holder in both the 100 metre and 200 metre events will be one of the biggest names once the Olympics go underway on August 5. There were doubts over his fitness but he’s managed to get past them and will be looking to cement his place in history by completing a third consecutive sweep at the track and field events.

2. Michael Phelps: United States

The record-holder for the most Olympic golds. Seven-time winner of the World Swimmer of the Year. Michael Phelps, the 31-year-old swimmer from Baltimore, is one of the sport’s greatest athletes. And yet there will also be a tinge of redemption to his story when he returns in the 2016 Olympics.

Phelps retired from swimming after the 2012 Olympics, having won four gold and two silver medals in the competition. But what followed were dark times – Phelps was arrested in 2014 for driving under the influence and admitted himself to rehab to overcome his struggles with alcohol and suicidal thoughts.

But the champion swimmer came out of retirement to become the first American male swimmer to qualify for a fifth Olympics. The world’s eyes will be on Phelps again as he seeks to add to his record-breaking achievements.

3. Dipa Karmakar: India

If there’s one Indian and only one you want to look out for, it's this one. Dipa Karmakar has blazed quite a trail with her progress so far. The first Indian female gymnast to qualify for the Olympics, the first Indian gymnast to participate in the Olympics since 1964, and the winner of an unprecedented gold at the test event of the Olympics, making her the first Indian to win a gold at a global gymnastics completion – and all this after struggling with flat feet when younger.

Karmakar is also one of the few gymnasts in the world who can perform the Produnova vault, considered one of the most dangerous in the world. Can she script history in Rio?

4. Caster Semenya: South Africa

Like the Indian athlete Dutee Chand, South Africa’s Caster Semenya will return to the Olympics with some vindication.

Semenya’s gender was called into question after she won the 800 metre sprint at the World Championships in 2008 and she was barred for more than a year. She did return in 2011, but question marks continued to hang around her.

However, the Court of Arbitration of Sport’s decision in July 2015, which ruled that athletes such as Semenya (and Chand) did not enjoy an advantage over other athletes due to high levels of testosterone, has come as a relief. And Semenya seems to be in amazing form in the build-up to Rio – she has posted the fastest times in the 800 metre category and is seen as a firm favourite for a medal.

5. Mo Farah: United Kingdom

The 33-year-old from Somalia is considered the United Kingdom’s greatest distance athlete. Farah shot into fame at the 2012 Olympics in London where, in front of an adoring local crowd, he achieved the rare distinction of winning gold in both the 5000 metre and 10,000 metre events. He then went on to win gold in the same categories twice at the 2013 and 2015 World Athletics Championships.

Now he looks forward to doing a double – winning another pair of Olympic golds in his second Olympics. There will be competition, especially from the Kenyan runners, but if he does win, we’ll get the chance to see his signature celebration, the “Mobot” once more.

6. Kohei Uchimara: Japan

Apart from Dipa Karmakar, if there’s another gymnast you should keep your eye on at the Olympics, it's 27-year-old Kohei Uchimura from Japan.

Nicknamed “Superman” for his incredible agility, Uchimura has come first in the all-around event at the World Champions six straight times, from 2009 to 2015. He’s also won silver in the same event at the 2008 Olympics in Beijing and topped it with gold at London in 2012.

Uchimura is widely regarded as among the greatest men’s gymnasts of all time, though he himself does not think too much about it. The 27-year-old has admitted that this could be the last Olympics where he is at the top of his game. But perhaps he’ll be able to sign off on a high, considering he is the overwhelming favourite to win gold in the event again.

7. Simone Biles: United States

Like Serena Williams in tennis, Simone Biles is a sportsperson who goes beyond her sport.

Just 18, she is the first African-American to be the world all-around champion in gymnastics, where she’s won the title at the World Championships in the last three years. She even has her own signature move: the “Biles”, which is a double flip with a half twist. An overwhelming favourite to win up to six medals at the Olympics, Biles is already on the cusp of history – and she’s still in her teens.

8. Ashton Eaton: United States

This 28-year-old Ashton Eaton is the “World’s Greatest Athlete”. No, it’s not a promotional buzzword coined by an advertiser – Eaton won the gold at the 2012 London Olympics in the decathlon. The winner of this event, which consists of ten track and field events, is traditionally recognised as the “World’s Greatest Athlete”.

But there’s more to Eaton. He’s not just the reigning Olympic champion, he’s also the reigning two-time world champion, a three-time world indoor heptathlon champion, and a world record holder to boot. Suffice to say he’s the favourite to defend his title. But don’t let that certainty stop you from tuning in to watch the world’s greatest athlete.