In 1895, Wilhelm Roentgen discovered X-rays while experimenting with cathode ray tubes. He noticed a fluorescent plate glowing in a dark room even when the tube was covered, leading him to take the first X-ray photo of his wife's hand. Roentgen could not explain the nature of these new rays, so he called them X-rays. In 1901, Roentgen received the Nobel Prize in Physics for his discovery. X-rays revolutionized medicine by allowing internal body structures to be visible, though early images lacked depth and clarity. Later developments like CT scans provided more advanced 3D imaging capabilities.