<P> Scholars who interpret The Wizard of Oz as a political allegory see the Emerald City as a metaphor for Washington, D.C. and unsecured "greenback" paper money . In this reading of the book, the city's illusory splendor and value are compared with the value of paper money, which also has value only because of a shared illusion or convention . It is highly likely that the Hotel del Coronado influenced its description in later books, as well as in the artwork by John R. Neill . </P> <P> David Williamson (whose brother - in - law wrote the Oz - inspired musical Oz (1976)) wrote a play called Emerald City (1987). The term is used as a metaphor by the character Elaine Ross, who describes Sydney as "the Emerald City of Oz", where people go expecting their dreams to be fulfilled only to end up with superficial substitutes and broken dreams . (Note that "Oz" can refer to "Australia" in colloquial Australian speech .) The 2006 Sydney New Year's Eve Festivities were entitled "A Diamond Night in Emerald City" also in reference to Williamson's play, and the "Diamond Night" alluded to the 75th anniversary of the opening of the Sydney Harbour Bridge in 2007 . (The bridge was the centerpiece of the celebrations). Subsequently, "Emerald City" has occasionally been used as an unofficial nickname for the city of Sydney . The head office of the Sydney - based merchant banking and private equity firm Emerald Partners is located on top of the Museum of Contemporary Art building on the Sydney Harbour foreshore, at Circular Quay . The firm was named after Baum's book and the David Williamson play . </P> <P> The American city of Seattle, Washington has used "The Emerald City" as its official nickname since 1982 . There is also a drink known as "Emerald City" that is associated with the city of Seattle . Eugene, Oregon is also referred to as the Emerald City, and the region has been known as the Emerald Empire as early as 1928 . </P> <P> Muntinlupa City is nicknamed as the Emerald City of the Philippines by the Department of Tourism . </P>

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