from Wikipedia Douala:
Douala is the largest city in Cameroon and the capital of Cameroon's Littoral Province. Home to Cameroon's largest port and its major international airport, Douala Airport, it is the commercial capital of the country. Consequently, it handles most of the country's major exports, such as oil, cocoa and coffee, as well as trade with Chad. It is also home to the Eko Market, the country's largest market.