Four-time Olympic gold medallist and Australian swimming star Ariarne Titmus has announced her retirement at the age of 25. She ends an incredible career with four world titles and eight Olympic medals. She took a year off after the Paris Games, where she famously defended her 400-meter freestyle title, before making her decision. Titmus mentioned a recent health scare that motivated him to concentrate on personal objectives away from the pool. Titmus, the 200-meter freestyle world record holder and an icon who helped Australia regain its position as a swimming superpower, is well-known for her epic rivalry with American Katie Ledecky.