City Museum in St. Louis transformed the former International Shoe building into an immersive environment built from salvaged architectural and industrial materials. Founded by Bob Cassilly and Gail Cassilly, the project began after they bought the mostly vacant factory in 1993, with visitors first admitted in 1996 and the museum formally opening on October 25, 1997. Its tunnels, slides, mosaics, sculptures, rooftop attractions, and outdoor MonstroCity made it one of the city’s most distinctive destinations. Blending artwork, playground, performance space, and landmark, it remained closely tied to Cassilly’s vision as it expanded through later additions and changes in ownership.