The classical age of Mesoamerica and the Andean region show how many societies and civilizations were able to take control of their areas and adapt to the challenges that faced them. From the civilization of Teotihuacán to the Maya in Mesoamerica, common beliefs and social and political patterns emerge to connect one to the other. In the Andean region, geography led to more isolation, and in North America, it was not until the introduction of Mesoamerican crops that agriculture could really be successful. The Pacific Islands also show an abundance of similarities and differences in their social and cultural adaptation to the region, sometimes, even on the same island, as the Counterpoint in the chapter explores on the island of Bougainville. In all of the areas examined, agriculture and trade helped lead to the formation of common civilizations, and while they all collapsed due to the fragility of their agricultural systems and their limited technologies, the scarcity of written records still complicates efforts to recover more exact histories.