With 500 days to go before the next Olympic Games starts in Japan, we look at 13 star athletes who could rewrite the record books
Who will be the headline acts at Tokyo 2020?
When the Japanese capital last hosted the Summer Olympics in 1964, the nation presented the Shinkansen, the world-famous bullet train that has become a global icon.
This time the Tokyo organisers promise to present the 'most futuristic' Games in Olympic history.
But which athletes will shine at Tokyo 2020?
We look at 13 stars who are hoping to make history at the next Olympic Games which start on 24 July 2020.
At Rio 2016, Simone Biles equalled the record haul of golds by a female artistic gymnast at an Olympic Games.
After taking some 18 months off, the American is better than ever and even defied a kidney stone to win medals in all six events - four golds, a silver and a bronze - at the World Championships in Doha late last year.
The record for Olympic gymnastics titles, and the most by any female athlete, is nine held by Larysa Latynina who represented the Soviet Union in 1956, 1960 and 1964.
Biles could match that with five golds in Tokyo, a number within her reach given that she claimed uneven bars silver and balance beam bronze in Doha.
No female gymnast has won five Olympic titles at a single Games, but the 21-year-old could be the one to achieve it.
And perhaps she could even match Vitaly Scherbo's six golds at Barcelona 1992.
Three more medals of any colour in Tokyo would see Biles pass Shannon Miller's tally of seven and become the USA's most decorated Olympic gymnast
Biles starts her 2019 season at the Stuttgart World Cup event this weekend.
When it comes to sustained excellence, few can match American shooter Kim Rhode.
The California native won double trap gold at Atlanta 1996 aged 17, making her the youngest female Olympic shooting champion.
After taking bronze at Sydney 2000, she regained her title at Athens 2004 before that event was discontinued.
No trouble for Rhode who switched to skeet and took silver at Beijing 2008 before going one better at London 2012.
And her bronze medal at Rio 2016 made her the first Olympian to win medals on five different continents, and the only woman to make the podium in six consecutive Games.
Now 39, Rhode has her sights set on a seventh Olympic appearance and says she could also compete in trap and the first trap mixed team event.
But skeet remains her number one discipline, and she set a new world record last April in Changwon to show she will be right in the mix come Tokyo.
The last time Teddy Riner tasted defeat in a judo bout was 13 September 2010.
The French +100kg ace has swept all before him since then, adding two Olympic golds to his bronze from Beijing 2008 and scooping a record haul of 10 world titles.
At 29, Riner still has years ahead of him in the sport and says he would like to be around for Paris 2024 in the city he was raised after being born in Guadeloupe.
His last competition was in November 2017 when he took the World Judo Open in Marrakech, Morocco.
'Big Ted' was due to return to action in Marrakech this month, but his coach Franck Chambilly told Olympic Channel that he would need more time in training before returning to peak sharpness and competition.
Gold at Tokyo 2020 would see Riner join Tadahiro Nomura on a record three golds, and move above him as the most successful judoka in Olympic history thanks to that Beijing bronze.
Ryoko Tamura-Tani is the most decorated athlete with five medals - two gold, two silver and a bronze - from 1992 to 2008.
LeBron James is bidding to match Carmelo Anthony's record of three golds and one bronze in men's basketball.
The LA Lakers star was in the USA side which was stunned by Argentina in the Athens 2004 semi-finals, as documented in the Olympic Channel film 'The Golden Generation'.
Normal service was restored in Beijing as the USA took gold before retaining the title at London 2012.
James missed Rio 2016 through fatigue after guiding the Cleveland Cavaliers to their first NBA title.
But with coach Gregg Popovich at the helm, King LeBron says he's keen to pull on the US jersey again at Tokyo 2020.
There could be history in women's basketball too as the United States bid for a seventh consecutive title.
Women's wrestling made its debut at Athens 2004 with Kaori Icho winning the 63kg division.
The Japanese retained her title at Beijing 2008 and London 2012 before making it four golds out of four in the 58kg class at Rio 2016.
She is the only wrestler to win four Olympic titles with team-mate Saori Yoshida having to settle for silver in Rio.
Yoshida announced her retirement in January, but 34-year-old Icho carries on.
Having taken two years out after the Rio Games, Icho returned with victory at the All Japan Championships before avenging a group defeat to fellow Olympic champion Risako Kawai to take December's national championships.
Her loss to Kawai was her first to Japanese opposition for 17 years.
But she said after her final victory that she had "room to grow and improve" which bodes well for her tilt at a fifth Olympic gold on home soil.
Already the record-holder for most Olympic medals won by an equestrian athlete, Isabell Werth will be 51 when Tokyo 2020 rolls around.
But the German dressage rider shows no sign of slowing down.
Werth claimed individual gold and team silver at Rio 2016, and won double gold at last year's World Equestrian Games in Tryon, North Carolina.
That triumph was an emotional one for Werth with her horse, Bella Rose, returning to action after four years out injured.
Had it not been for a loss of form ahead of London 2012, she might well have joined Kim Rhode in winning Olympic medals in five different continents.
Two more medals for Werth in Tokyo would see her draw level with canoeist Birgit Fischer as her country's most decorated Olympian.
One medal is all Jason Kenny needs at Tokyo 2020 to become the most successful cyclist in Olympic history
Kenny took silver behind team-mate Chris Hoy at Beijing 2008 with the pair joining forces for gold in the team sprint.
He then clinched double gold at London 2012 before retaining both titles at Rio 2016, and taking the keirin which Hoy had won at the previous two Games.
A month after Rio 2016, he married four-time Olympic track cycling champion Laura Trott with their first child Albert born in 2017.
He was in Great Britain's team sprint trio at last month's World Championships in Poland, losing out to eventual winners the Netherlands in the quarter-finals.
But the 30-year-old is an expert at preparing for the Olympics and he is currently level with Hoy on six golds, a British record and the most won by any cyclist.
One more medal of any colour would see him go to eight medals, matching Britain's most decorated Olympian Bradley Wiggins.
Katie Ledecky is the undisputed queen of middle and long-distance swimming.
The American sprung to prominence at the age of 15 with gold in the 800m at London 2012.
She followed that up with four titles at the 2013 World Championships in Barcelona and five at Kazan in 2015.
At Rio 2016, she anchored the United States to silver in the 4x100m freestyle relay before winning gold in the 400 free, 200 free, 4x200m freestyle relay, and again in the 800 free.
And Ledecky has an extra gold to aim for at Tokyo 2020 with the 1500m freestyle - in which she is the world record holder and three-time world champion - added to the programme.
In her sights is fellow American Jenny Thompson's record for a woman in the pool with eight golds out of a total of 12 medals.
And Larisa Latynina's nine titles, the most of any woman in Olympic history, is definitely within reach.
The only four-time Olympic medallist in beach volleyball, Kerri Walsh Jennings, hopes to bid for more hardware at Tokyo 2020.
The tall American actually competed in indoor volleyball at Sydney 2000, helping the United States to fourth place, before making the switch to the sand.
With Misty May-Treanor, she won gold at Athens 2004, Beijing 2008 and London 2012.
May-Treanor's retirement ended the greatest partnership in women's beach volleyball history, but Walsh Jennings formed a new pairing with London 2012 silver medallist April Ross.
The pair enjoyed considerable success but were found wanting at Rio 2016, going down to Agatha and Barbara in the semi-finals before taking bronze.
Ross has a new partner in Alix Klineman with Walsh Jennings teaming up with Brooke Sweat.
And Walsh Jennings and Sweat have started out on the road to Tokyo, winning the 3* event in Sydney.
No player has won three individual gold medals in badminton, but China's Lin Dan could be the first.
Lin beat Lee Chong Wei in the final at Beijing 2008, and did the same at London 2012 to retain his title.
But the Malaysian had his revenge in the Rio 2016 semi-finals before Lin went down to future world champion Viktor Axelsen in the bronze medal play-off.
'Super Dan' has not been so super of late, crashing out in the first round no fewer than nine times in 2018.
With each country allowed a maximum of two players in the Olympic singles, Lin faces stiff competition from defending Olympic champion Chen Long and world number two Shi Yuqi, champion at the 2014 Youth Olympic Games.
Lin suffered an early exit at this month's All England Championships, an event he has won six times, but the all-time great might have one more trick up his sleeve to end his career on a high.
The most successful woman in Olympic athletics history, and the most decorated athlete in the history of the IAAF World Championships, plans to be back for more at Tokyo 2020.
As an 18-year-old, Allyson Felix secured silver at Athens 2004 before repeating that achievement at Beijing 2008 as well as taking gold in the 4x400m relay.
It was a case of third time lucky at London 2012 as she finally won the 200m, adding golds in the 4x100m and 4x400m relays having finished fifth in the 100m.
A former world champion in the individual 200m and 400m, Felix gave birth to her first child in November eight weeks prematurely after playing a key role in the Los Angeles 2024/2028 candidature.
Daughter Camryn spent the first few weeks of her life in newborn intensive care, with Felix saying, "I didn't care if I ever ran track again."
But the 33-year-old has history in her sights with her tally of nine just one behind the American track and field record held by Carl Lewis.
And Felix is three short of the all-time record held by Finnish long-distance runner Paavo Nurmi who won 12 medals from 1920 to 1928.
Shaun White is the greatest snowboarder in history with three Olympic halfpipe gold medals and a raft of titles from the Winter X Games.
But he has also enjoyed success as a skateboarder, helped by having Tony Hawk as an adviser from the age of nine.
White won vert crowns at X Games 13 and X Games 17 in 2007 and 2011 respectively, and he wants a piece of the action when skateboarding makes its Olympic debut at Tokyo 2020.
There is no vert class in Tokyo with 'The Flying Tomato' trying to qualify in park rather than street.
He has been practising hard in recent months, and the 32-year-old hopes to be one of three Americans in the competition.
That's no easy task, but if he makes it he could face a familiar foe from the slopes.
White is seeking to emulate Eddie Eagan as the only athlete to win gold medals at both the Olympic Winter Games and the 'Summer Olympics'.
American Eagan won gold in light-heavyweight boxing at Antwerp in 1920 and the four-man bobsleigh at Lake Placid in 1932.
China have won every table tennis gold on offer at the last three Olympic Games, and the team will be keen to extend that run despite strong opposition from the hosts in Tokyo.
Ma Long took individual gold at Rio 2016 to become the fifth player to complete a career Grand Slam comprising the Olympic Games, the World Championships and World Cup.
Ma is the outstanding player of his generation with his Rio gold coming during his record 34 consecutive months at the top of the world rankings.
Before Tokyo comes into view, he will be seeking to add to his tally of 10 World Championship triumphs as he defends individual and team titles next month in Budapest.
Team-mate Zhang Jike, Ma's victim in the Rio 2016 final, also has three Olympic golds.
And with China overwhelming favourites for the team title, whoever wins the individual crown could be the history maker.
Like Zhang, defending women's champion Ding Ning has amassed three golds and a silver at Olympic Games.
The 28-year-old will aim to retain her world title in Budapest next month, and a repeat of her double gold in Rio would see her move to a record five Olympic titles.