The Black Swan is a large waterbird which can have a wingspan of six feet. Native to Australia, it is an official state emblem of Western Australia and also a symbol for the Aboriginal people. Discovered in 1697 by Dutch explorer William de Vlamingh, Europeans were astounded that they existed as they had only seen white swans. Thus, in what is called the Black Swan Theory, a black swan is also defined as a large-impact, unpredicted event such as the 9-11-01 attack on the United States. Black Swans were introduced to Europe and America as ornamental waterbirds but some such as this one have escaped into the wild.