How were X-rays discovered?

The answer

In 1895, Wilhelm Röntgen was experimenting with cathode ray tubes when he noticed a fluorescent screen across the room glowing, despite being too far from the tube for cathode rays to reach it. He realized an unknown form of radiation was passing through solid objects. He called them 'X-rays' because of their mysterious nature. When he placed his wife's hand in front of a photographic plate and exposed it to the rays, he produced the first medical X-ray image, clearly showing her bones and wedding ring.