In time they will go down as two of the greatest Olympians of all time – one, the biggest showmen sport has known, the other, the most decorated of them all.
Rio 2016 will be memorable for many things but what it may also come to be regarded for is the golden goodbyes of Usain Bolt and Michael Phelps.
The Jamaican sprinter and the American swimmer are set to bow out before the cycle towards Tokyo 2020 becomes too intense.
Whether they will do so with any more medals to their name will be two of the more intriguing storylines of the coming Games.
Bolt has six golds from the last two Olympics. Already the first man to win successive 100m finals (Carl Lewis was awarded gold in 1988 after Ben Johnson’s expulsion) Bolt is bidding to cement his status as not only the fastest man on the planet, but also the greatest sprinter of all time.
Standing in his way is the arch-villain to his superhero status – Justin Gatlin, the last man not named Bolt to win Olympic 100m gold 12 long years ago.
Gatlin has since served a suspension for drug use and his very name – no matter whether he is clean or not – represents all that is unpalatable about athletics in this day and age. Their dual in the 100m and 200m will headline the second week.
The first week belongs to the swimmers, and for a fourth Games in a row, Phelps is the name that once again stands out. Thirty-one years old now, and back from retirement for a fifth Olympics, there will be no repeat of the six golds he won in Athens, the record eight Olympic titles he claimed in Beijing, or the eight more medals in London (four of them gold), because he is only doing three events.
But watching him in action in the 100m and 200m butterfly, and the 200m individual medley in the first week of the Games, will be one of the better spectacles of the first week – especially if South African Chad le Clos can go fingter-tip to finger-tip with him in the butterfly again. Remember his Dad at London 2012? ‘Unbelievable’.
The heir apparent to Phelps’ crown is another American, Katie Ledecky.
Just 19 years of age, she is the biggest name in women’s swimming and already an Olympic champion after winning gold in the 800m freestyle in London.
She defends that crown and is favourite to win the 400m and 200m freestyle in Rio.
Across the pool at the Olympic Aquatics Stadium, the dominant force in diving is China. Look for two-time world champion Qui Bo to be Tom Daley’s nemesis in the 10m platform.
Chris Froome, coming off the back of a third Tour de France win in four years, is favoured to win either the men’s road race or the time trial, and his chances in the former have been enhanced by the decision of world champion Peter Sagan to choose to contest the mountain biking disciplines instead of more tradition pursuits.
Expect the colourful Slovakian to make mountain biking a box-office event.
And when it comes to the more mainstream sports, look no further than world No 1 Novak Djokovic in the tennis, and Neymar flying the flag for hosts Brazil in the football.
The international field in Rio is as strong as ever.