One of the 19th century’s most important discoveries happened entirely by accident. German physicist Wilhelm Conrad Rontgen was experimenting with passing electrical currents through gas-filled tubes similar to fluorescent light bulbs when he noticed a screen starting to glow. It was illuminated by invisible rays coming from a tube that was covered in black paper, meaning they had the power to penetrate solid objects. Rontgen created the first X-ray image by swapping the screen for a photographic plate. The image revealed the bones in his wife’s hand.
