What was one similarity between ancient African kingdoms of Ghana, Mali, and Songhai?

The ancient African kingdoms of Ghana, Mali and Songhai resemble each other a lot. They have similarities in between them. It does not encompass rain forests or mountainous terrain. Nor are they anywhere near the European border. Instead, all three kingdoms are part of major trading routes.

This gives them enormous benefit and an asset that they can exploit to their heart’s content. The countries can avail the trade routes and develop their export and import businesses for the better of their countries and their people. There is enormous potential in these routes and can boost the economy if utilized appropriately.