Leon Marchand demolished the US Open and NCAA record in the 500 freestyle, swimming a 4:02.31.
For context, the NCAA record had been lowered by a total of 2.6 seconds in the last 29 years. Marchand just lowered it by 3.9 seconds.
Read more about Leon's swim here:
https://swimswam.com/leon-marchand-drops-mind-boggling-402-31-in-the-500-free-to-obliterate-his-own-ncaa-record/