Spa World is one of two new parks, the other being Futureworld, at the Delos theme park in the 1976 movie, Futureworld. The Delos Park in Futureworld is three times the size that it was in Westworld. During Futureworld, Westworld is closed and deserted.
Delos spent $1.5 billion in the two in-world years between Westworld and Futureworld replacing everything in Medieval World and Roman World, and building the new sections of Spa World and Futureworld.
Spa World, a garden of pleasure, where old age and pain have been eliminated.