In the 1790s, trade was a major part of the U.S. economy. At this time, most goods were sent by boat. So, the country needed cities with ports. The city of New Orleans was especially important. It sits on the Mississippi River, and it borders the Gulf of Mexico. Find out more in The Louisiana Purchase, a title in the Building Our Nation series. Building Our Nation is a series of AV2 media enhanced books. A unique book code printed on page 2 unlocks multimedia content. These books come alive with video, audio, weblinks, slideshows, activities, hands-on experiments, and much more.