The Silk Road was not a single road, but a vast network of land and sea trade routes connecting China with the Mediterranean. It was officially 'opened' during the Han Dynasty when Emperor Wu sent his envoy, Zhang Qian, to the West to seek alliances against nomadic tribes. While his military mission failed, he returned with reports of sophisticated civilizations and superior 'heavenly horses' in Central Asia. This sparked a desire for trade. Silk, a luxury secret kept by China for millennia, was the most famous export, but the routes also carried spices, precious stones, and paper. More importantly, the Silk Road was a conduit for ideas. Buddhism traveled from India to China via these routes, and later, Islam and Christianity spread as well. The exchange of technologies like gunpowder and the compass eventually paved the way for the modern world. It remained the primary artery of global trade for over 1,500 years.