When you think about excellence in the marathon, the name Deena Kastor inevitably jumps to mind. After all, the 52-year-old held the American record in the distance for a whopping 19 years, setting it first in London in 2003, then bettering her own mark just three years later when she became the first American woman to run under 2:20. In fact, Kastor—a three-time Olympian, World Marathon Majors champ, World Cross Country medalist, and holder of national records from the 5K up to the 26.2—was drawn to distance from the very first time she hit the track.

Long before Roberta Gibb and Sara Mae Berman unofficially ran the Boston Marathon (1966 and 1969 respectively), Arlene Pieper Stine became the first woman to officially finish a sanctioned marathon in 1959, when she ran the Pikes Peak Marathon—ascent and descent—in 9:50:20 when she was 29. She was accompanied by twelve men and a horse. Pieper Stine ran in the men's category and was not given a special category or fanfare for her historic finish. She never ran another marathon and her pioneering accomplishment fell into obscurity until 2009.

Upon turning 50 years old, Yolanda Holder decided to do something different for her birthday. While others in her circle of family and friends opted for elaborate parties, expensive experiences or trips, or even purchasing long-desired goods, Yolanda, on the other hand, set out to walk 50 marathons in 50 weeks. She didn't just meet that goal—she crushed it, completing 66 marathons in 52 weeks. And she never stopped. Now 67, Holder has become one of the most accomplished ultra-endurance athletes in the world. She has set Guinness World Records, all while breaking barriers as a race walker in a runner's world. Yolanda is also the first African American woman to achieve numerous milestones in multi-day racing.