The Blue Mountains of New South Wales, Australia, are found approximately 100 kilometers west of Sydney. They are a range of sandstone geological structures that reach to at least 1,190 meters AHD. The Blue Mountains are not as the name suggests a range of mountains but rather a series of cliffs surrounding a plateau with rugged eroded gorges of up to 760 meters depth. A large majority of the Blue Mountains is incorporated in the Greater Blue Mountains Area World Heritage Site and its constituent seven national parks and a conservation reserve.