Mongol empire, empire founded by Genghis Khan in 1206. Originating from the Mongol heartland in the Steppe of central Asia, by the late 13th century it spanned from the Pacific Ocean in the east to the Danube River and the shores of the Persian Gulf in the west. At its peak, it covered some 9 million square miles (23 million square km) of territory, making it the largest contiguous land empire in world history.
To prevent the spread of communism in Southeast Asia is why did President Kennedy get the United States involved in the Vietnam War so the reason was the usage of containment policy.
