Brave New World, the new expansion to 2010's Civilization 5, will add the ability for your civilization to trade directly with other nations and independent city-states, as outlined in this new gameplay trailer.
Trade routes take the form of caravans over land and cargo ships over sea; the latter can hold more and make your kingdom more wealthy. Both, however, are at risk of being destroyed by hostile forces if not adequately protected. Trade routes will be limited both in length and the number available at any one time, says the video, but structures and World Wonders can be built to help alleviate some of these shortcomings.
Brave New World hits July 9 in North America and July 12 worldwide.