Mali Empire
The Mali Empire's most important industry was gold. People in the ancient world were drawn to it. The Mali Empire (Timbuktu in particular) was a huge trading center for the gold industry. Camel caravans would come to the area before leaving across the trans-Saharan trade routes. The empire had so much gold that it caused the market to crash for a period of time when Mansa Musa brought almost a ton of gold to Cairo. The army of the Mali Empire was massive.