Imagine walking into a dark room and seeing thousands of stars above you. That is what visitors felt when the Adler Planetarium opened in Chicago on May 12, 1930. A German company called Zeiss had built a special projector that could display stars, planets, and the Milky Way on a domed ceiling. The machine sat in the center of the room and used dozens of tiny lenses to create pinpoints of light. Each dot was placed in the exact position that matched where a real star appeared in the sky. Max Adler, a Chicago businessman, paid for the building. He believed that everyone deserved a chance to study the universe, not just scientists with expensive telescopes. The planetarium became wildly popular. More than 700,000 people visited in its first year. For the first time, city residents who had never seen a truly dark sky could watch the stars move and learn the names of constellations. Today, modern planetariums use digital projectors that can zoom past planets, fly through galaxies, and even show what the sky looked like thousands of years ago.