He argued that control of the Eurasian landmass (Europe, Asia and the Middle East), which contained the bulk of the world’s population and natural resources, was the major geo-political prize.

As time passed, energy (first crude oil then natural gas), became increasingly integral to this concept and its strategic significance cannot be overstated.

Remarkably, Mackinder’s theory has remained equally valid, if not more so, in the modern era - although key “pivot areas” for exercising control have evolved.