In this lesson, students learn that the Columbian Exchange resulted in an enormous exchange of goods, resources, and institutions between the Old World and the New World and that the results of the Exchange were both positive and negative. The lesson begins with an activity in which students are divided into two groups: Old World consumers and New World consumers. Students are given food cards to keep or trade within each group, and later, among consumers from both groups. Although the expansion of trade provides students with more choices and has positive effects, some trades result in negative effects. A second activity summarizes some of the positive and negative impacts of the Columbian Exchange, some of which students experience in the fi rst activity. A final activity describes Tenochtitlan, the capital city of the Aztec civilization that had a relatively well-developed economy in the 15th century despite the lack of capital resources such as iron tools, wheels, and draft animals. The Aztecs adopted legal institutions that protected property rights and supported a market economy. The Spanish, who conquered the Aztecs in 1521, replaced these with institutions that restricted the ability of the native population of Mexico to produce and trade. Similar restrictions were imposed by European colonizers in other New World areas. Students learn that, in addition to the exchange of plants, animals, and culture, the exchange of institutions between the Old World and the New World had an important impact on the future economic growth of countries in the Western Hemisphere.