I want to know the answer to the following question:
What festival was celebrated in the 1950s in recognition of the city's Mexican and Spanish past?
All the background I'm provided with is that "In the 2010s there was a proposal for a large-scale celebration of the 100th anniversary of Balboa Park, but the plans were abandoned when the organization tasked with putting on the celebration went out of business.". Is that enough to answer the question?