In the eight years since Katie Ledecky set her first world record in the 800-meter freestyle, she has swum the grueling race 31 times in competitive finals, on five different continents and in dozens of cities, against scores, perhaps hundreds of challengers. And never, not once, has she been beaten.
Over almost a decade of unprecedented dominance, Ledecky has defended her 2012 Olympic gold medal, and defended her 2013 world title three times. She’s broken her own record four times. She’s touched the wall in under 8 minutes and 14 seconds on 23 different occasions. No other woman in history ever has.