This document discusses the expansion of trade routes between 300 BCE and 1500 CE across Afroeurasia and the Americas. Empires required long-distance networks for military and political communication, which also facilitated cultural exchange. The development of writing systems and world religions like Buddhism, Christianity, and Islam further stimulated cultural diffusion across regions. Trade routes like the Silk Roads connected East, South, and Central Asia and allowed for the spread of goods, religions, and diseases across vast areas.