Famously used by Mao Zedong in his 1925 ci-poem 《沁园春·长沙》: 怅寥廓，问苍茫大地，谁主沉浮？('Brooding over this immensity, I ask the vast earth: who rules its rise and fall?')
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Literary. In modern speech you'd reach for 辽阔 (liáokuò, same pinyin, different second character — 'broad and wide') or 广阔 (guǎngkuò) for 'vast'.
