The Saint Louis Science Center in St. Louis, Missouri, grew from a planetarium founded in 1963 into one of the largest science museum complexes in the United States. Its modern form emerged through the merger of the Museum of Science and Natural History with the planetarium site, completed when the remodeled facility reopened in 1985. A major 1991 expansion on the former Falstaff Brewing Corporation headquarters site increased its size sevenfold and linked its buildings by a skybridge over Interstate 64. The center became one of the world’s most visited science institutions and continues to expand its exhibits, theater technology, programs, and outreach.