What was the role of trade that developed in west africa?

Trade has played an important role in the economy of West Africa since very early times. As early as 300 CE, camel caravans carried salt from mines in the Sahara Desert to trading centers along the Niger River in present-day Mali. Their mission was to exchange the salt for the gold that was mined in forests near the headwaters of the Niger. West Africa's first kingdom, Ghana, became wealthy and powerful because it controlled the trade routes and commercial activities in its region.

There’s no picture, but i’ll give you a few of expeditions. lewis and clark began in 1804, louisiana purchase 1802, james town 1607