The
Hilton Palacio del Rio in San Antonio was constructed by HB Zachry for the 1968
Hemisfair World's Fair using prefab technology. It was reputedly the first hotel so built, and remains in operation.
The technology proved so successful that Zachry used it to construct a hospital on the northern edge of downtown SA as a sample to show a Middle Eastern bigwig what they could build in the desert. It also remains in operation.