On June 3, 1966, Roberta "Bobbi" Gibb watched the Boston Marathon from the sidelines, one year after she had submitted her entry form and been rejected with a letter explaining that women were physiologically incapable of running marathon distances.

In 1966, she had run anyway. She hid in the bushes near the starting line, wearing a hooded sweatshirt to disguise herself, and slipped into the crowd of male runners. She finished in 3:21:40 — ahead of two-thirds of the field.

When word spread through the crowd that a woman was running, spectators cheered her on. The governor of Massachusetts shook her hand. The official response was that she had not officially run, because women could not officially run.

The Amateur Athletic Union did not allow women to officially enter road races until 1972. When Kathrine Switzer entered Boston in 1967 with a number — using her initials to obscure her sex — a race official physically tried to push her off the course.

Bobbi Gibb ran Boston again in 1967 and 1968, setting what would have been course records in both years had she been allowed to officially compete. Her times were faster than the first women's official finishers years later.

The BAA retroactively recognized her as the first woman to run Boston in 1996, thirty years after the fact.