World record progression 100 metres freestyle

The first world record in the 100 metres freestyle in long course (50 metres) swimming was recognised by the International Swimming Federation (FINA) in 1905. In the short course (25 metres) swimming events, the world's governing body recognizes world records since 3 March 1991.

Source: Wikipedia — World record progression 100 metres freestyle (CC BY-SA 4.0)