In swimming, no stage is as big as the Olympics, with the United States and Australia placing multiple swimmers in nearly every final heat.
Great Britain, France, Italy and Russia are also expected to challenge for gold medals in Rio, but one of the smallest countries in Europe might be the biggest surprise in the pool.
For Danish freestyler Anders Lie Nielsen, the pressure of the Olympics is nothing new.
A participant in the 2012 London Games and World Championship meets, Nielsen sticks to simple wisdom before stepping on the blocks.
"Everyone is just human there. Nobody is anything spectacular, there are big names but don't be intimidated, just go in there and have fun," Nielsen told Omnisport.
"For your nerves, just focus on your own stuff. If you keep focusing on the guy next to you, you are going to get nervous because they are probably better than you. You have your own lane, anything can happen. Do what you do in practice, it is just swimming, it's not rocket science."
Nielsen, who hails from Farum, Denmark, finished 23rd in the 200-metre freestyle at the World Championships in Kazan, Russia, last year.
He also anchored his country's 4x200m freestyle relay team that finished 13th in London.
But the 25-year-old expects bigger things in Rio alongside relay team-mates Daniel Skaaning, Magnus Westermann and Soren Dahl, who set a Denmark national record in Kazan en route to a 12th-place finish.
"We keep moving up the ranks, I hope we can make the A final [in the 4x200m freestyle relay in Rio]," Nielsen said, adding that he personally hopes he can make it to the semi-finals of the 200m freestyle.