Poland's tertiary education institutions; traditional universities, as well as technical, medical, and economic institutions, employ around tens of thousands of researchers and staff members. There are hundreds of research and development institutes. However, in the 19th and 20th centuries many Polish scientists worked abroad; one of the most important of these exiles was Maria Skłodowska-Curie, a physicist and chemist who lived much of her life in France. In 1925 she established Poland's Radium Institute.