Contemporaries considered Genghis Khan the founder of Mongolia who united nomadic tribes. During Genghis Khan’s reign, the Great Silk Road became a single political environment, and Mongol conquests significantly facilitated communication and trade between Northeast Asia, the Muslim Southwest Asia, and Christian Europe—expanding the cultural horizons of Eurasian civilizations. But at the same time, Genghis Khan was one of the most ruthless conquerors in history. His campaigns led to a sharp decline in population in some regions, largely due to mass killings and famine. According to various estimates, the number of people who died as a result of Genghis Khan’s military campaigns ranges from four to sixty million. Read the most terrifying pages of the great commander’s biography in the new book of the series "The Most Complete Biography."