A planetarium is a special building or room designed to show people the wonders of the night sky. Inside, a large dome-shaped screen displays stars, planets, and other celestial objects. Using advanced projectors, visitors can experience realistic simulations of the universe, making it feel like they are traveling through space. Many planetariums also offer educational programs and shows about astronomy, helping people learn about topics like black holes, galaxies, and the solar system. They are popular destinations for schools and families, providing a fun way to explore the mysteries of the universe together.