Many of Asia's greatest cities were destroyed in the space of about 50 years: Constantinople in 1206 (almost Asian!), Beijing in 1215, Samarkand in 1220, Baghdad 1258. History might have looked very different if these cities had been saved.
For example, it's likely that much of the scholarship of western antiquity was lost in the closely spaced sacks of Constantinople and Baghdad. The Mongol destruction was particularly thorough in their destruction of scholarship: "The books from Baghdad’s libraries were thrown into the Tigris River in such quantities that the river ran black with the ink from the books."[1]