The International Day of Planetariums is observed worldwide every May 7. This day, which was inaugurated by the Italian Association of Planetaria and is sponsored by the International Planetarium Society, celebrates planetariums and their role in educating the public about astronomy. The date commemorates the first regular operation of the Zeiss planetarium at the Deutsches Museum in Munich on May 7, 1925. On this day, planetariums around the globe host various events, including lectures and exhibitions, often with discounted or free entry to encourage public participation. The observance aims to foster collaboration within the international planetarium community and to reconnect people with the stars in an era of light pollution. Since its inception in 1991, the event has grown to include participation from regional and national planetarium associations in Europe, the Americas, Asia, and Australia.