In 1872 Yellowstone was established as a National Park. The name caught the public's imagination and by the close of the century, other National Parks had been declared, not only in the USA, but also in Australia, Canada, and New Zealand. Yet as it has spread, the concept has evolved and diversified. In the absence of any international controlling body, individual countries have been free to adapt the concept for their own physical, social and economic environments. Some have established national parks to protect scenery, others to protect ecosystems or wildlife. Tourism has also been a...