The military campaigns launched from the Mongolian steppe by Genghis Khan and his successors between 1206 and the mid-fourteenth century, which created the largest contiguous land empire in history, killed tens of millions of people, connected Eurasia into a single trading system, and restructured the political order from China to Eastern Europe.
The Mongols killed more people as a proportion of world population than any event before the twentieth century. They also created the conditions for the Silk Road's greatest flourishing, the transmission of plague across Eurasia, and the diplomatic and commercial connections that made the Renaissance possible. Destruction and connection — both, inseparably.