Tokyo Olympics will be the first Olympics of the 21st century which will not see Michael Phelps either diving into the pool or standing on a podium with a gold medal. The legendary swimmer entertained sports fans for more than a decade, broke records, and won medals (mostly gold) for fun. Today he turns 36.As the world of the Olympics is set for a post-Phelps era, here is a look at his five greatest achievements.Michael Phelps' extraordinary achievements5) The youngest male ever to set a world record in swimmingMichael Phelps (right)At 15 years and 9 months, Michael Phelps set the world record in 200m butterfly at the 2001 World Aquatic Championships, finishing the race in 1:54.58. Phelps thereby became the youngest male ever to set a world record in swimming. He broke his own record seven times and held the record for the fastest 200m butterfly for 18 years.His record was broken in 2019 when Hungarian teenager Kristof Milak clocked 1:50.73 at the 2019 World Aquatic Championships.STOP THE PRESSES! A fantastic new World Record from 19-year old Kristóf Milák of Hungary in the Men’s 200m Fly beating Michael Phelps old mark of 1:51.51, set a decade ago in Rome, with a new time of 1:50.73…Outstanding! 💪👑#Swimming #FINAGwangju2019 pic.twitter.com/Qr2DiOGDG3— FINA (@fina1908) July 24, 20194) Michael Phelps' gold rush at the 2007 World Aquatic ChampionshipsMichael Phelps in action at XII FINA World ChampionshipsMichael Phelps dominated the 2007 World Championships in Melbourne. He claimed a gold medal in each of the seven events he contested in, and set a world record in five of those.Phelps won golds in 200m and 400m individual medley, 100m and 200m butterfly, 200m freestyle, and 4×100m and 4×200m freestyle relay. With seven world titles to his name, Phelps tied with fellow American swimming great Mark Spitz for most wins at a major international meet.Also read: 5 American swimmers other than Caeleb Dressel tipped to impress at Tokyo Olympics 20203) Michael Phelps' Great Eight at Bejing 2008Michael Phelps winning a record eight golds at Beijing Olympics 2008Michael Phelps holds the record of winning the most gold medals at a single edition of a summer Olympics.At Bejing Olympics 2008, Phelps clinched gold in men’s 200m freestyle, men’s 4x100m freestyle relay, men’s 4x200m freestyle relay, men’s 100m butterfly, men’s 200m butterfly, men’s 200m individual medley, men’s 400m individual medley and men’s 4x100m medley relay.He created world records in seven out of the eight events. With eight golds, Phelps surpassed Spitz for the record of most individual golds at a single Olympic edition. Spitz won seven golds at the 1972 Olympics.2) Michael Phelps rules in Rio 2016Michael Phelps in action at Rio Olympics 2016In his last Olympic appearance at Rio Olympics 2016, Michael Phelps clinched five golds and one silver medal. Phelps was making a comeback at the Olympics as he had retired from professional swimming after the London Olympics in 2012.At Rio, Phelps claimed golds in 4x10m freestyle, 200m butterfly, 200m individual medley, 4x200m freestyle relay and 4x100m medley. He claimed silver in his final individual event at the Olympics as he was beaten by Singapore’s Joseph Schooling in 100m butterfly.1) Michael Phelps' accomplishments at Athens 2004Michael Phelps at Athens Olympics 2004At Athens, Michale Phelps claimed his first Olympic gold with the 400m individual medley. This was the start of a medal heist which would continue for the next four Olympics. Gold in 400m individual medley was followed by bronze in 4x100m freestyle and 200m freestyle.Phelps upped the ante soon and went on to claim golds in 4x200m, 4x100m, 200m individual and 100m individual. His seven-medal haul made him stand behind Spitz for the record of most medals at an Olympic game.Michael Phelps also won four golds and two silvers at the London Olympics 2012. With a grand total of 28 medals, Phelps remains the most decorated Olympian ever.To put Phelps’ medals in perspective, he has won more medals than 161 countries who have ever participated at Olympics.2️⃣3️⃣ days to go!Michael Phelps holds the record for most gold medals with 23 - more than double the next best 🥇#Tokyo2020 pic.twitter.com/IdM5pTg115— 7Olympics (@7olympics) June 30, 2021He still holds four world records. Phelps holds records in 400m medley (4:03.84) 4x100m freestyle relay (3:08.24), 4x200m freestyle relay (6:58.55) and 4x100m medley relay (3:27.28).Also read: What makes Caeleb Dressel the fastest swimmer on the planet?