In 1789, a German chemist, Martin Heinrich Klaproth, announced that he had discovered a new element in the dull black mineral pitchblende. He named it after the planet Uranus, itself discovered only eight years earlier.
Little interest was shown in uranium for more than 100 years, until in 1896 the French physicist Antoine Becquerel found that it caused a sealed photographic plate to become exposed, a phenomenon that Marie Curie, a young doctoral student from Poland working in Paris, named "radioactivity."
Curie found that pitchblende contained two further new elements. Working with her husband, Pierre, the Curies announced the discovery of polonium in 1898 ("from the name," they wrote in their paper, "of the original country of one of us."). Showing dedication to match anything seen in science, the Curies spent a further four years isolating another new, radioactive element from pitchblende: radium. But it was the element discovered by Klaproth, the dense metal uranium, that would become the most sought after and have the greatest historical impact.