Modern pentathlon is an unpredictable sport where the least likely of competitiors can come from out of nowhere to win a medal.
Take for example Czech Republic's David Svoboda; he was ranked twentieth in the world when he made his Olympic debut in London and wasn't expected to contend for a medal.
Svoboda started strong as he took 26 of 35 fencing bouts to jump out to an early lead. He traded the lead with China's Cao Zhongrong after the swimming competition but reclaimed it after the equestrian event.
Svoboda finished sixth the the combined run/shoot event which would secure him enough points to just edge out Zhongrong by 24 points to win gold.
By contrast, Russia's Aleksandr Lesun, who was widely viewed as the favorite to win after placing first at the World Championships prior to London, finished a disappointing fourth. He was in third place at the start of the combined run/shoot event but dropped to fourth after Hungary's Adam Marosi had a strong showing.
It remains to be seen who, if anyone, will follow in Svoboda's footsteps.
However, we do know that there will be several favorites, many of them returning from previous Games to stake their claim to the ultimate prize.
The aforementioned Lesun is expected to be a strong favorite to earn a medal after winning gold at Worlds in 2014 and silver in 2015.
After finishing in the top five at Worlds the past two years, France's Valentin Beluad is also expected to contend for a medal along with teammate Valentin Prades. Should either of them reach the podium, it would be historic for France who has yet to win an Olympic medal in the pentathlon.
Hungary has the most gold medals in the competition, with four, and will send the London bronze medalist Marosi back to compete in Rio. Marosi placed in the top 3 at three World Cup events in 2016.
Egypt's Amro-El Geziry and his brother Omar, will also participate in the games. Amro is the husband of pentathlete Isabella Isaksen who will represent the United States in the women's individual.
Amro, who took second at Worlds in 2014, is expected to have a shot at a medal. He is one of the best swimmers in the contest having won every swimming event on the 2016 World Cup circuit and at Worlds.
Nathan Schrimsher will be the sole U.S. representative in the men's individual competition. He is an active member of the U.S. Army and was the first U.S. athlete in any sport to qualify for Rio.
He will be in a strong position to contend for a spot at the podium. He is ranked ninth in the world and finished seventh at the 2016 World Cup final. This was the best finish at the event by an American man in eight years.
Schrimsher looks to become the first American man to win an Olympic medal in the pentathlon since Robert Beck at the Rome Games in 1960 where he won bronze.