The world’s very first human x-ray was of Wilhelm Konrad von Röntgen’s wife’s hand and substantial ring. Röntgen had been experimenting with X-rays and found that a sheet of paper covered with a barium platinocyanide compound would continue to glow even after he took the paper away. So of course, he asked his wife to place her hand on it!
This is the x-ray that started it all, folks! Röntgen went on to win the first Nobel Prize for Physics in 1901. You can read more here.