Final answer:
Before the discovery of Australia by Captain Cook, the biggest island in the world was Greenland. This status remained even after the discovery of Australia, which is considered a continent, not an island due to its vast size. Greenland, surrounded by the Arctic and Atlantic Oceans, is 2,166,086 square kilometers in size.
Step-by-step explanation:
Before the discovery of Australia by Captain Cook, the largest island in the world was Greenland. Despite its icy climate and harsh conditions, it was recognized as the world's biggest island.
Geographically, an island is defined as a landmass surrounded by water. Although some may argue that continents like Australia could be considered islands, traditionally the term is applied to smaller landmasses. When Captain Cook discovered Australia, it was soon recognized as a continent rather than an island due to its vast size.
Greenland, with an area of approximately 2,166,086 square kilometers, was the largest known island before Australia's discovery. Its size and the fact it's completely surrounded by the Arctic and Atlantic Oceans confirm its status as an island. Even after the discovery of Australia, Greenland remains the largest island in the world when Australia is considered a continent.
Learn more about Greenland