question: What happened to many of the structures developed for the World Fairs ?
answer: Most were eventually rebuilt , using castings of the original façades to retain the architectural style .
turker_answer: Most of the structures developed for the World Fairs were eventually rebuilt , using castings of the original facades to retain the architectural style .
rule-based: Many most were eventually rebuilt , using castings of the original façades to retain the architectural style of the structures developed for the World Fairs .