The Maya civilization emerged in the Yucatán peninsula and into what is now Central America and southern Mexico around A.D. 200. The Maya were known for being great astronomers; they used the stars to come up with calendars. The Maya continued to thrive until A.D. 900 which is when they abandoned their cities for an unknown reason. Around A.D. 700 a group called Hohokam was developing a large system of irrigation canals in what is now south-central Arizona. The Hohokam grew corn, cotton, beans, and squash. By 1500 the Hohokam tribe deserted their land likely due to flooding.
The Maya had great talent for mathematics and engineering. They began creating very accurate calendars by using the positions of the stars. The also build huge pyramids, some of which were 200 feet tall and used them as a center piece for all of the Mayan cities. Most anthropologists think the reason that the Maya abandoned there cities in A.D. 900 was because farmer had exhausted the regions soil, which caused famine, riots, and the collapse of all their cities.
The Hohokam were known for building very complex canals to carry water for miles and miles so that it can easily get to different farms. They used both Gila and salt rivers to supply water throughout the group. The Hohokam survived by growing corn, cotton, beans, and squash for food. The Hohokam flourished for more than 1,000 years, but in 1300, they started to abandon their cities,