Kathrine Switzer will run in the Boston Marathon on Monday, 50 years after she entered using the name "K.V. Switzer" to become the first woman to participate in what was then an all-male race. "The marathon was a man's race in those days; women were considered too fragile to run it," she wrote in a New York Times essay. "But I had trained hard and was confident of my strength."

Race director Jock Semple famously tried to rip Switzer's number off her while she was running, a moment that was captured in a now-famous photograph. "A big man, a huge man, with bared teeth was set to pounce, and before I could react he grabbed my shoulder and flung me back, screaming, 'Get the hell out of my race and give me those numbers!'" Switzer recalled in her memoir.

50 years after #BostonMarathon tried to push Switzer off the course for being a woman, she's running again today! https://t.co/45KxPXm1VX pic.twitter.com/C5c4JIa7do — Allison K. Lange (@aklange1) April 17, 2017

Switzer finished the marathon in four hours and 20 minutes, but was later disqualified because she was a woman.

Women were finally officially allowed to enter the Boston Marathon in 1972. Switzer, now 70, rejoins the Boston Marathon on Monday with more than 30 marathons under her belt, including a win in New York in 1974. It will be her first time running the Boston race since 1976, and her first marathon since 2011. She will race in the same number that Semple tried to rip off her back.

"Everything changed," Switzer told CNN affiliate WBZ-TV, reflecting on her historic run. "I said, 'This is going to change my life, maybe going to change women's sports and change the world.'" Jeva Lange