She was regarded as the "Mother of Modern Physics" for her work with radioactive materials and the discovery of elements such as polonium and radium. Unfortunately, her study took a heavy toll on her health, eventually leading to aplastic anemia, which led to her death. The radioactivity not only damaged her, but it also impacted the majority of her things, including her clothes, furniture, and books. Marie Curie's notes must now be preserved in a lead box more than a century later since they are still radioactive (and will be for another 1,500 years!).