Uranium is a radioactive metal that was discovered in 1789. It has since been used to develop nuclear weapons and power, though it poses health risks if exposed. Key events include its discovery, uses in pottery and glass, Marie Curie's studies showing it is radioactive, the Manhattan Project developing the first nuclear bomb using uranium-235, and current uses in nuclear power and military applications. The document also outlines uranium's effects on human body systems and potential health issues from exposure.