Article: The spread of Greek culture and language throughout the Near East and Asia owed much to the development of newly founded cities and deliberate colonization policies by the successor states, which in turn was necessary for maintaining their military forces. Settlements such as Ai-Khanoum, situated on trade routes, allowed Greek culture to mix and spread. The language of Philip II's and Alexander's court and army (which was made up of various Greek and non-Greek speaking peoples) was a version of Attic Greek, and over time this language developed into Koine, the lingua franca of the successor states.

Question: Ai-Khanoum was situated on what kind of routes?
trade