When Frida Kahlo was 18 years old, she seemed on the verge of claiming the life she’d imagined. The daughter of a German artist father and a Mexican mother, Kahlo had wanted to be a doctor since she was a child. She was pursuing that dream through her studies at the National Preparatory School in Mexico City, about an hour’s drive from her hometown of Coyoacan. Though she was clearly a talented artist, art remained at the periphery of her life.

On September 17, 1925, that all changed. After a day of classes, Kahlo and her friend Alejandro Gomez Arias boarded a bus heading toward Coyoacan. Minutes after they sat down on a wooden bench, the bus turned a corner and slammed into an electric trolley car traveling at full speed. “The streetcar crushed the bus against the street corner,” Kahlo told author Raquel Tibol in Frida Kahlo: An Open Life. “It was a strange crash, not violent but dull and slow, and it injured everyone, me much more seriously.”

After the crash, Kahlo felt the bottom had dropped out of everything she’d known. But as her body healed—a process that took many months—her views of life and art radically transformed. While confined to bed, seeing very few visitors, she began painting more and more. “The loneliness led her to start expressing in a way that she wasn't doing before,” says performer Vanessa Severo, creator of the play Frida… A Self Portrait. “She was telling her story by painting it.”

As Kahlo’s career progressed, themes of pain and recovery emerged at the heart of her work. “She pushed through the pain and didn’t hide it,” Severo says. “She expressed it.”

That uncompromising honesty became one of her signature artistic qualities.

When the bus Kahlo was riding hit a trolley car, she suffered serious internal injuries as a long metal rod tore through her midsection. On the scene of the accident, an onlooker tried to remove the metal rod from Kahlo’s body. “When he pulled it,” Arias recalled, “Frida screamed so loud that no one heard the siren of the Red Cross ambulance.”

Kahlo’s injuries were so severe that she had to be encased in a full-body plaster cast. The carefree years of her childhood, when she’d relished exploring the mysteries of life, came to an abrupt end. “After the accident, everything changed,” says art historian Celia Stahr, the author of Frida in America__. “She describes it as like lightning.” In a letter, Kahlo wrote Arias that she now lived on “a painful planet, transparent as ice.”

What sustained Kahlo through interminable days in bed was her painting. Her parents gave her a lap easel so she could paint while convalescing, and they mounted a mirror in her bed’s canopy to help her paint her own face.

As Kahlo slowly recovered, she started to venture outside again, but “it's not the life that she knew before,” Stahr says. Having been so immersed in the joys of artistic creation, Kahlo set aside her dream of becoming a doctor and dedicated herself to art.

Kahlo’s Self-Portrait in A Velvet Dress (1926), which she painted during her recovery, reveals the major changes she was going through. The turbulent seascape in the background signified her life’s upheaval, and for the first time, she portrayed herself on canvas with a prominent unibrow. “What we see happening is she’s going through this whole rebirth process,” Stahr says. “She said later in life that she was the one who gave birth to herself.”

As Kahlo gained confidence and self-assurance as a painter, she began alluding to a range of traumas she’d endured. In The Bus (1929), a young woman who resembles Kahlo sits on the wooden seat of a public bus—a scene that conjures up the last moments before Kahlo’s fateful accident.

Later on, Kahlo portrayed her physical and psychological pain in starker terms. In Henry Ford Hospital (1932), Kahlo depicts herself in a hospital bed bleeding after a miscarriage, tears sliding down her face. And in The Two Fridas (1939)—painted after Kahlo divorced muralist Diego Rivera—a version of Kahlo with her heart ripped open sits holding hands with another, healed version of herself.

“I suffered two serious accidents in my life, one in which a streetcar knocked me down,” Kahlo famously said. “The other accident was Diego.”

Kahlo’s depiction of her suffering was groundbreaking in its directness. In the early 20th century, “you didn’t have woman artists putting their own personal traumas in their art,” Stahr says. “It’s very personal, but it's also political, because of how women are viewed, how they're marginalized.”

That honesty, radical for its time, is what so many people connect with in Kahlo’s work decades later. “Instead of hiding what is painful and hard, she openly did share it,” says Severo, herself an artist living with disability. “She taught me that I can just stand up and be exactly who I am.”