A remote volcanic archipelago in the Southern Ocean is literally growing before our eyes.

Countries & Cities · Published 30 September 2026 Swipe more like this →

In short: Located halfway between Australia and South Africa, the McDonald Islands are a rare, undisturbed wilderness. Once dormant for 75,000 years, the islands' volcanoes have erupted repeatedly since 1992, dramatically reshaping the landscape and doubling the size of the main island through fresh lava flows and new volcanic cones.

The Heard Island and McDonald Islands territory sits in the Southern Ocean, roughly 1,700 km from Antarctica. While Heard Island is dominated by the snow-capped Big Ben volcano, the McDonald Islands are smaller, consisting of McDonald Island, Needle Island, and Meyer Rock. These islands are the emergent peaks of submarine volcanoes resting on the Kerguelen Plateau, a massive underwater feature that deflects Antarctic circumpolar waters and influences global geomorphological processes.

For 75,000 years, the McDonald Islands remained volcanically quiet. That dormancy ended in December 1992 with a submarine eruption. Subsequent activity in 1997 and 2001 transformed the archipelago's geography. Lava flows and pyroclastic activity filled in bays and merged the formerly separate Flat Island into the main landmass. By 2005, satellite imagery confirmed further growth, and in total, these eruptions have effectively doubled the island's surface area. Today, the highest point is Maxwell Hill, reaching 230 metres.

These islands serve as a vital, alien-free laboratory for scientists. Because they are virtually free of introduced species and human modification, they provide a pristine environment to study biological and evolutionary processes. Millions of marine birds and mammals, including penguins, albatrosses, and seals, rely on the islands for breeding. The area is managed as a strict nature reserve by the Australian Antarctic Division, with stringent quarantine controls to protect its ecological integrity from pathogens and non-native species.

Beyond biology, the islands are a geological treasure. They offer evidence of the world's longest-running plume system, providing researchers with unique isotopic data on mantle composition and crustal plate interactions. As the glaciers on nearby Heard Island retreat in response to climate change, the entire territory remains a critical site for monitoring the health of the Southern Ocean ecosystem and understanding the ongoing physical changes shaping our planet.

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