15. X-ray
While we take them for granted now, the x-ray as a diagnostic tool for identifying tooth decay and broken bones came about by accident. In 1895, German physicist Wilhelm Conrad Röntgen was experimenting with electric currents through cathode-ray tubes discovered that an unknown or “X”-radiation could be seen through cardboard encasing the tube. He made the first x-ray image of his wife’s hand and wedding ring. And the rest is history.
