The World Islands

The World Island: This is the largest of the three regions and encompasses Eurasia, which includes Europe, Asia, and parts of the Middle East. Mackinder argued that whoever controlled the "Heartland" within the World Island (roughly referring to the vast expanses of Eastern Europe and Russia) would have the potential to dominate the world due to its vast resources, population, and strategic position.

The Offshore Islands: These are the islands surrounding the World Island, including the British Isles, Japan, and others. Mackinder saw these islands as important players in global geopolitics due to their naval power and ability to project force.

The Outlying Islands: These are the remaining islands and continents, such as the Americas, Africa, and Australia. According to Mackinder's theory, these regions were less central to global politics because they lacked the resources and strategic positioning of the World Island.

Mackinder's theory laid the foundation for later geopolitical thinking, and it influenced strategies during both World War I and World War II. The idea that controlling the "Heartland" of Eurasia was key to global dominance played a role in shaping the policies of various world powers throughout the 20th century.

It's important to note that while Mackinder's ideas were influential, they are not without criticism and have been subject to debate among geopolitical scholars. Geopolitical theories have evolved since Mackinder's time, but his concept of the World Island remains a significant part of the history of geopolitics.