Heard and McDonald Islands

Made an Australian national park in 1997 and a UNESCO World Heritage Site the same year, Heard and McDonald Islands hold the only active volcano in all of Australian territory, Big Ben, whose summit stays capped by Australia's only active volcanic glacier. Having historically never had introduced species — unlike almost every other subantarctic island, colonised in their day by rats or cats brought by whalers — it is reckoned one of the island ecosystems least disturbed by direct human activity anywhere on the planet, with no eradication programme needed because there is nothing to eradicate.