Polonium and radium

Polonium and radium were discovered, demonstrating intense radioactivity. Thorium too was recognized as radioactive.This led to the coining of the term 'radioactivity' and awards for the Curies.
 Marie and Pierre Curie France 1898 Polonium and radium

Polonium and radium were discovered, demonstrating intense radioactivity. Thorium too was recognized as radioactive.This led to the coining of the term 'radioactivity' and awards for the Curies.