She studied in secret under Russian occupation, moved to Paris alone with almost nothing, and became the only person ever to win Nobel Prizes in two different sciences. At every turning point, you make the call.

Bronya had finished medical school. The agreement was complete. It was now Maria's turn.

Paris meant the Sorbonne — one of the few universities in Europe that admitted women. It also meant leaving Poland, her father, and everything she knew. Her French was imperfect. She had almost no money. She would live in a rented room in the Latin Quarter, so cold in winter that the water in her washbasin froze overnight. Some days she fainted from hunger.

She enrolled in the Faculty of Sciences. She was one of very few women in the building. She changed her name from Maria to Marie.

Marie had been assigned to study the magnetic properties of steel. She needed laboratory space. A Polish physicist introduced her to Pierre Curie — a 35-year-old researcher who had already made significant contributions to physics and who ran a laboratory at the School of Physics.

Pierre Curie had never met anyone quite like Marie. He fell in love quickly. He proposed. Marie refused.

She had always planned to return to Poland. She was Polish. Her country was occupied. She believed she had a responsibility to bring science home — to teach, to build institutions, to contribute to Polish intellectual life under occupation. She had never meant to stay in France forever.

Pierre proposed again. He said he would move to Poland with her if she asked. He would learn Polish. He would give up his own career if necessary.

Marie had given birth to their first daughter, Irène. She needed to choose a topic for her doctoral thesis — she would be the first woman in France to pursue a doctorate in physics.

Henri Becquerel had recently discovered that uranium emitted mysterious rays that could penetrate solid objects and expose photographic plates without any external energy source. Nobody understood what this was. It was a puzzle, largely ignored by the scientific establishment, considered a minor curiosity.

Marie's advisors urged her to choose something safer, more established, less likely to end in failure. She was a new mother. She was a woman in a field that barely acknowledged her existence. She should not take unnecessary risks with her career.

Marie chose uranium.

The 1903 Nobel Prize in Physics was to be awarded for the discovery of radioactivity. Henri Becquerel had discovered the phenomenon. Pierre and Marie Curie had characterized it, named it, and isolated two new radioactive elements.

The initial Nobel Committee nomination included only Becquerel and Pierre. Marie's name was not on it. A Swedish mathematician named Magnus Gösta Mittag-Leffler wrote privately to Pierre, warning him that Marie had been excluded. Pierre was furious. He wrote back that he would refuse to accept the prize if Marie was not included as a joint recipient.

But Pierre's position only mattered if Marie backed it completely.

On April 19, 1906, Pierre Curie stepped off a curb in the rain on the Rue Dauphine. A horse-drawn wagon struck him. He died instantly. He was 46.

Marie was 38. She had two daughters: Irène, 8, and Ève, 1. She had a laboratory full of ongoing research. She had a grief she described in her diary as something that felt like drowning in it.

Two months later, the University of Paris offered her Pierre's professorship. She would become the first female professor in the university's 651-year history. She would have to walk into a lecture hall in front of hundreds of people — students, press, curious members of the public — and teach physics to a room that had never had a woman at the front of it.

In November 1911, Marie Curie was awarded the Nobel Prize in Chemistry — making her the only person in history to win Nobel Prizes in two different sciences.

At almost the same moment, French newspapers published allegations of a romantic affair between Marie and physicist Paul Langevin — a married man and former student of Pierre's. The scandal was devastating. Crowds gathered outside her house. Someone threw a rock through her window. Her children were taunted at school.

The Nobel Committee wrote to her privately, suggesting she not attend the ceremony in Stockholm. The implication was clear: a woman at the center of a moral scandal should not appear in public accepting a prize.

Marie Curie read the letter. Then she wrote back.

Marie Curie died on July 4, 1934, from aplastic anemia — a disease caused by long-term exposure to ionizing radiation. She was 66. She had spent 40 years handling radioactive materials with her bare hands, carrying them in her coat pockets, storing them in unlocked desk drawers. Her personal notebooks are still radioactive today and are kept in lead-lined boxes at the Bibliothèque nationale de France. Researchers who want to read them must sign a waiver and wear protective equipment.

She had two Nobel Prizes, a laboratory she built from nothing, 32 named scientific discoveries, and a daughter — Irène Joliot-Curie — who won her own Nobel Prize in 1935, the year after Marie died.

She had also been the first woman to win a Nobel Prize, the first person to win two, the first female professor at the Sorbonne, and the first woman admitted to the French Academy of Medicine.

She had done all of this from a leaking shed, on almost no money, in a language that was not her first, in a century that did not think she should be there at all.