Classic book in geopolitics by Halford Mackinder. Published in 1919.
<bdi><a href="https://en.wikipedia.org/wiki/en:Halford_Mackinder" class="extiw" title="w:en:Halford Mackinder"><span title="English geographer, academic, and politician (1861-1947)">Halford Mackinder</span></a>
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