The Great Barrier Reef, the world's largest coral reef, lies a short distance off the north-east coast and extends for over . Mount Augustus, claimed to be the world's largest monolith, is located in Western Australia. At , Mount Kosciuszko is the highest mountain on the Australian mainland. Even taller are Mawson Peak (at ), on the remote Australian external territory of Heard Island, and, in the Australian Antarctic Territory, Mount McClintock and Mount Menzies, at and respectively.