Wilhelm Conrad Röntgen discovered X-rays while experimenting with cathode rays in a vacuum tube. He noticed that a screen across the room began to glow, even when the tube was covered. He soon realized that an unknown form of radiation was passing through solid objects, including human tissue, but was partially blocked by bone. The first medical X-ray ever taken was of his wife's hand, clearly showing her bones and wedding ring. This invention revolutionized medicine overnight, as it allowed doctors to 'see' inside the human body without surgery for the first time. It became an essential tool for diagnosing fractures, tumors, and foreign objects. Röntgen refused to patent his discovery, believing it should belong to humanity, and he was awarded the first-ever Nobel Prize in Physics in 1901.