The Caravan is the emissary of a civilization's economy. By guiding these units to foreign cities, you will immediately get a wealth of gold added to your treasury, the amount of which depends on the distance the Caravan has traveled from the city in which it was built. The owner of any city where a Caravan arrives also receives a small amount of gold. Like Settlers, however, Caravans are defenseless and can be captured by another civilization, though this will cause a war.