Opening in 1951, Aquarena Springs was a resort and amusement park located on Spring Lake in San Marcos. Attractions included glass-bottom boat tours, a sky ride, and a submarine theater. (For the latter, the audience partially descended into the water to see a performance by the "Aquamaids," young women wearing mermaid tails who stayed underwater by sipping from air hoses.) Arguably the most popular attraction was Ralph the Swimming Pig, who began each show by taking a "swine dive" into the lake to drink from a milk bottle held by a trainer. At its peak, Aquarena Springs attracted 250,000 visitors annually, remaining a popular tourist destination from the 1960s through the 1980s. 

 

Texas State University purchased the property in 1994, initially planning to update the theme park and use it to underwrite academic research. Dwindling attendance and surging costs, however, made operating the park—then known as the Aquarena Center—impossible. Ralph made his final performance in February 1996. Texas State ultimately tore down most the facility to return Aquarena Springs to its original condition. (The area is one of the oldest continually inhabited locations on the continent.) What remained eventually became the Meadows Center for Water and the Environment, an educational center dedicated to water research. The center still conducts glass-bottomed boat tours.