The biggest factor in bringing Native Americans into contact with one another was the development of trade networks. These networks allowed for the exchange of goods, ideas, and technologies between different tribes, and they also facilitated the spread of cultural and religious practices. Trade networks were often established along rivers, lakes, and other natural waterways, and they could extend over long distances. For example, the Hopewell culture, which flourished in the Ohio River Valley from about 100 BCE to 500 CE, had a trading network that reached as far as the Gulf Coast and the Great Plains. The Mississippian culture, which developed in the Mississippi River Valley from about 800 to 1500 CE, had a trading network that extended from the Great Lakes to the Gulf of Mexico. These trade networks played a vital role in the development of Native American societies, and they helped to create a sense of interconnectedness among different tribes.