Marie Curie did not invent the X-ray. Wilhelm Conrad Röntgen discovered X-rays in 1895.

Marie Curie is famous for her work in radioactivity. She and her husband, Pierre Curie, are credited with:

* Discovering the radioactive elements polonium and radium.

* Pioneering research into radioactivity, including its applications in medicine.

Marie Curie's work with radioactivity led to her receiving the Nobel Prize in Physics in 1903 (shared with her husband and Henri Becquerel) and the Nobel Prize in Chemistry in 1911.