Antarctica
Volcanic sub-Antarctic islands closed to casual visitors.
Heard Island and the McDonald Islands are an Australian external territory in the southern Indian Ocean, around 4,000 km southwest of Perth. Heard Island is dominated by Big Ben, an active glaciated volcano whose summit, Mawson Peak, is Australia's highest mountain. The islands are a UNESCO World Heritage Site, with large colonies of penguins, seals and seabirds and no introduced species.
There is no tourism, no permanent population and no facilities. Access requires a permit from the Australian Antarctic Division, and nearly all visits are by research voyages, with only very occasional expedition ships reaching the area. Weather is severe all year, and any landing is only realistic in the southern summer.