The discovery of the X-ray by Wilhelm Roentgen is interesting in that it was made by accident. Roentgen was experimenting with uranium, when he left for the weekend leaving a large piece of uranium ore in a drawer on top of a sealed box of photographic film. When the film was later developed, he noticed that it had been exposed. After some time of trying to figure out what had happened, Roentgen realized that the uranium ore was emitting G-rays and X-rays which had exposed the film. This later lead to his experiments with this new idea, and eventually lead to his great discovery.
In 1896 a physicist wrote:
ÓOn reading Professor Ršntgen's papers on a new type of radiation, I could not help feeling this to be a fairy tale . . ."