UPDATE 1-Swimming-Ledecky punches ticket to Paris Games, Walsh sets world record in Indy

Katie Ledecky qualified for her fourth Olympic Games and Gretchen Walsh set a world record on the opening night of the U.S. Olympic Trials for swimming in Indianapolis on Saturday.

Katie Ledecky qualified for her fourth Olympic Games and Gretchen Walsh set a world record on the opening night of the U.S. Olympic Trials for swimming in Indianapolis on Saturday. As expected, seven-time gold medalist Ledecky dominated in the 400m freestyle championship, finishing in 3:58.35 before a crowd of 20,689 fans at Lucas Oil Stadium, home of the NFL's Indianapolis Colts.

"I never imagined I'd get to go to a fourth Olympic Games," Ledecky said. "I'm excited to get to Paris for Team USA."

Paige Madden was second with a personal best time of 4:02.08. Ledecky is widely considered the greatest female swimmer of all time and is just the eighth American swimmer to make at least four trips to an Olympic Games, where she will look to add to her tally of 10 Olympic medals.

Walsh kicked off night with a bang, setting a world record in the women's 100m butterfly to send a message to the world with just over a month to go before the Games. Walsh led from the outset, made the turn at a world record pace and looked up in disbelief after she touched the wall in 55.79 seconds as the crowd erupted.

Her performance in the semi-final heat beat the previous record of 55.48 seconds, which was set by Sweden's Sarah Sjostrom in 2016. The trials will determine the U.S. team for Paris and are being held over nine consecutive nights in Indianapolis, which has transformed into a swimming paradise complete with a 66-foot replica of the Eiffel Tower located near the downtown stadium.

The throng of red, white and blue clad fans was the biggest to ever witness a swim meet, breaking the record of 16,000 set at the Rio Olympics in 2016.