> natural defenses Not really. While China improved its “natural defenses” by very unnaturally invading and subjugating Tibet it is still ringed by hostile cou

> natural defenses Not really. While China improved its “natural defenses” by very unnaturally invading and subjugating Tibet it is still ringed by hostile countries or, in the case of Russia and North Korea, highly temperamental countries with very few natural barriers apart from the Himalayas which only covers one side. This is the reason the Great Wall was built.