Marie Curie discovered the radioactive element radium.

Discovery of Radium
Marie Curie, a Polish-French physicist and chemist, discovered the radioactive element radium in 1898 along with her husband Pierre Curie. They discovered radium while conducting research on uranium and its radioactive decay products. After the discovery, Marie Curie isolated radium in its pure form and determined its atomic weight.

Contribution to Science
Marie Curie's discovery of radium had a significant impact on science. It opened up new avenues of research in nuclear physics and led to the development of new medical treatments for cancer. Curie's work on radium also led to the development of radiation therapy, which is still used today to treat certain types of cancer.

Recognition and Awards
Marie Curie's contributions to science were recognized with numerous awards and honors. She was the first woman to win a Nobel Prize, receiving the award in physics in 1903 for her work on radiation. She later won another Nobel Prize, this time in chemistry, for her discovery of radium and polonium. Curie was also the first woman to become a professor at the University of Paris.

Conclusion
Marie Curie's discovery of radium was a significant contribution to science and has had lasting impacts on medical treatments and radiation therapy. Her groundbreaking work on radioactivity and the discovery of radium led to numerous awards and honors, including two Nobel Prizes.