 Radiation has been around since the creation of the universe. It is a natural part of our lives and existence on Earth. Each and every day, we're bombarded by natural sources of radiation, coming from outer space, the environment, and even from within ourselves. What we know about radiation, its effects, and their related health hazards, are shaped by events in politics, science, pop culture, and public health. The events described here provide a snapshot of the emerging story of health physics as it relates to modern times. The study of radiation and its health effects, and the science related to controlling health hazards associated with ionizing radiation, which we call health physics, began more than 100 years ago. In the decade before 1900, millions of acres of Indian territory in the U.S. were opened to settlers in Oklahoma, South Dakota, and Montana. Alice Island opened in New York Harbor, and the first modern Olympic games were held in Athens, Greece. In science, German physicist Wilhelm Röntgen passed an electric current through a low-pressure gas and discovered invisible rays that cause fluorescent screens to glow. Because of their unknown nature, he gave them the name X-rays. The following year, Thomas Edison developed the fluoroscope, which becomes the standard for medical X-ray examinations. No radiation protection was used, as the dangers of X-rays were not yet recognized. The same year, French physicist Henri Becquerel discovered the phenomenon of radioactivity when photographic plates were exposed to uranium samples that emitted penetrating rays similar to X-rays. Within a year, Polish physicist and chemist Marie Curie was investigating radioactivity and discovered two new elements, radium and polonium. The first warnings of possible adverse effects of radiation, specifically X-rays, came from Thomas Edison, William J. Morton, and Nikola Tesla, who reported that eye irritations occurred during experiments that used X-rays in fluorescent substances.