Women haven't exactly crossed the finish line when it comes to gender equality, but we've certainly come a long way since Kathrine Switzer first hit the pavement at the Boston Marathon.
It was 1967 when Switzer, then a 20-year-old journalism student at Syracuse University, became the first woman to officially enter the historic marathon.
At the time, women were woefully marginalized in the world of athletics. According to CNN, Switzer had been training with the men's cross-country team at Syracuse when she decided to enter the race, with little encouragement from her coach. In her memoir, Switzer recalled the Syracuse coach telling her the 26-mile marathon was too long for a "fragile woman."
Now, after running 39 marathons, 70-year-old Switzer will run in this year's Boston Marathon, likely with more people cheering her on than in 1967.
Switzer's inaugural Boston Marathon wasn't without its controversy.
A few miles into the marathon, race director Jock Semple chased Switzer own and ripped her bib off of her.
"Instinctively I jerked my head around quickly and looked square into the most vicious face I'd ever seen," Switzer wrote in her memoir, according to CNN. "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!'"
On Monday, Switzer will run wearing the same number once stripped from her by an angry man who didn't want to see a woman in his race. After Switzer finishes the race, the Boston Marathon will officially retire the number in her honor.
Looking back, Switzer said she knew Semple's attack — which was captured in an iconic photo — would be a tipping point for female athletes.
"Everything changed," she told CBS Boston. "I said, 'This is going to change my life, maybe going to change women's sports and change the world.'"