Possible Clues:

• Route that facilitated the spread of Buddhism
• Ancient Eurasian trade route
• Part of Polo's path
• Marco Polo was on it for 24 years
• Old trade route to China
• Caravan route disturbed dark soil
• Ancient trade route from China
• Unhappy about type that's run old, old way of trading
• Bar progress along this way east?
• Ancient Asian trade route