Katie Ledecky secured her spot in her fourth Olympic Games, while Gretchen Walsh broke a world record on the first evening of the US Olympic Swimming Trials in Indianapolis on Saturday. Ledecky, a seven-time gold medalist, excelled in the 400m freestyle event in front of 20,689 spectators at Lucas Oil Stadium, the home of the NFL's Indianapolis Colts. 'I never imagined I'd get to go to a fourth Olympic Games,' Ledecky expressed. The 27-year-old from Maryland attributed her longevity in the sport to her coaches and teammates, stating, 'I feel like I enjoy this more and more each year and I think that's a testament to the people around me my whole career.' Paige Madden came in second with a personal best time of 4:02.08 but has not yet qualified for the Games. Ledecky, often regarded as the greatest female swimmer of all time, is now the eighth American swimmer to qualify for at least four Olympic Games, aiming to increase her collection of 10 Olympic medals. Walsh made a remarkable start by setting a world record in the women's 100m butterfly, clocking in at 55.79 seconds, surpassing the previous record of 55.48 seconds set by Sweden's Sarah Sjostrom in 2016. Indiana native Aaron Shackell also earned his first Olympic berth with a win in the 400m freestyle. The trials, which will decide the US team for Paris, are being held over nine nights in Indianapolis, which has been transformed into a swimming hub featuring a 66-foot replica of the Eiffel Tower near the downtown stadium. The event attracted the largest crowd ever for a swim meet, exceeding the previous record of 16,000 set at the Rio Olympics in 2016.