On Prison World, the Loma Prieta earthquake on October 17, 1989 was far more devastating than in Earth Prime. It led to San Francisco being evacuated and the city becoming a maximum security federal penitentiary.
On Prison World, internal combustion engines have been replaced with electrical cars.
The idea of a major city being turned into a maximum security penitentiary was taken from John Carpenter's Escape from New York, where Manhattan was cut off from the surrounding boroughs, and turned into the nation's only Superman prison.
The San Francisco Prison is actually set in the futuristic looking Plaza of the Nations in Vancouver.
This episode's title references El Cid (1043-1099) who was an actual hero in medieval Spain.