And tens of thousands of people participated in the 121st annual Boston Marathon Monday. Among the runners was 70-year-old Kathrine Switzer, who in 1967 became the first woman to ever complete the 26.2-mile race as an official entrant. At the time, the marathon was male-only, so she entered under the name K.V. Switzer. Officials tried to force her off the course after a few miles, but she persevered and finished in four hours and 20 minutes. This is Kathrine Switzer.

Kathrine Switzer: “I was the only female running wearing a bib. There actually was another woman in the race who jumped out of the bushes and ran. But what kept me going was I had to make the decision. I mean, of course I felt scared and humiliated and embarrassed. This official was attacking me in front of the press truck, for heaven’s sakes. But my boyfriend bopped the official and sent him out of the race instead. And I ran on to finish. But I made the decision to finish because I felt, if I dropped out, then everybody would say, 'See, women are not welcome. They're always barging into places where they’re—they can’t do it anyway. And she’s just a clown.’ And I knew I had to finish to prove that women could, should and be allowed to get opportunities for women in running. So that was very, very important for me. If I had quit, it would set women’s running and women back.”

That was Kathrine Switzer, the first woman officially registered for the Boston Marathon to complete the race. This year, she finished the race in four hours and 44 minutes, wearing the same bib, number 261, that she’d worn in 1967. The winners of this year’s Boston Marathon were Edna Kiplagat and Geoffrey Kirui, both of Kenya.