The Saint Louis Science Center, founded as a planetarium in 1963, is a collection of buildings including a science museum and planetarium in St. Louis, Missouri, on the southeastern corner of Forest Park. With over 750 exhibits in a complex of over 300000sqft, it is among the largest of its type in the country, and according to the Association of Science and Technology Centers, is one of the top 5 science centers in the United States. In 1991, it was the most visited science center in the world. As of 2007, the complex hosts 1.2 million visitors each year, with another 200,000 served through offsite programs at schools and community centers.
The first building of the current complex, the Planetarium, opened in 1963, hosting about 300,000 visitors per year. In 1983, it was combined with an existing Museum of Science and Natural History that had been located in Clayton, Missouri, and the Planetarium was renamed as the Saint Louis Science Center. In 1991, a major expansion increased the size of the facility seven-fold, adding a main building and Omnimax theater across Interstate 64 from the Planetarium. In 1997, an air-supported building, the Exploradome, was added next to the main building, and in 2003, a Community Science Resource Center southeast of the main building was added to the complex. The northern and southern sections of the Science Center are connected via a pedestrian bridge over the interstate, which also has science exhibits, such as radar guns which visitors can use to investigate traffic patterns.
Admission to the Science Center is free through a public subsidy from the Metropolitan Zoological Park and Museum District. The Center is one of only two science centers in the United States which offers free general admission.