History is full of long and legendary highways but none โ€“ frankly โ€“ come close to the Silk Road. Itโ€™s not just the magnitude (at least 4,000 miles, in more than 40 countries) but the mythic potency of the project. The world was cleft into east and west in the Middle Ages.

But long before, the Silk Road โ€“ which has existed in one form or another since the fourth century BC โ€“ breached any such divide. While trade was its raison dโ€™รชtre โ€“ Chinese silk, of course, but also salt, sugar, spices, ivory, jade, fur and other luxury goods โ€“ the road forged deep social, cultural and religious links between disparate peoples.

And

The Silk Road was not a road, but a network. The central caravan tract followed the Great Wall, climbed the Pamir Mountains into Afghanistan, and crossed to the Levant. Along the way were spurs branching off to river ports, caravanserai, oases, markets and pilgrimage centres. Journeys demanded meticulous preparation: the Silk Road and its tributaries cut through some of the harshest, highest, wildest places on Earth.