Radium is a rare, radioactive metal that glows faintly in the dark with an eerie greenish-blue light. Discovered in 1898 by scientists Marie and Pierre Curie, radium was one of the first elements found that naturally gives off energy in the form of radiation.

When radium was first discovered, people didn't understand how dangerous radiation could be. Companies painted watch dials and instrument panels with radium paint so they would glow in the dark, making them easy to read at night. Pilots used radium-painted instruments to fly in darkness. The women who painted these dials, called the Radium Girls, became seriously ill because they were unknowingly poisoning themselves with radiation.

Today we know that radium is extremely hazardous to human health. The radiation it emits can damage living cells and cause cancer. Scientists now handle radium with great care, using special protective equipment and storing it in lead containers that block radiation.

Despite its dangers, radium helped scientists unlock crucial discoveries about atoms and energy. The Curies' work with radium laid the groundwork for nuclear medicine, which now helps doctors treat cancer. Marie Curie became the first woman to win a Nobel Prize for this research, though the very substance that made her famous ultimately contributed to her death from radiation exposure.