Colorado is a state located in the Rocky Mountain region of the United States of America. The climate of Colorado is quite complex compared to most of the United States. The typical south-north/cooler-warmer variation in other states is not generally applicable in Colorado. Mountains and surrounding valleys greatly affect local climate. The region that is today the State of Colorado has been inhabited by Native Americans for more than 13 millennia. Colorado also has a reputation for being a state of very active and athletic people. According to several studies, Coloradoans have the lowest rates of obesity of any state in the US. Colorado hosts seven of the Nation’s 100 largest natural gas fields and two of its 100 largest oil fields.