Colorado's grape growing regions contain some of the highest elevation vineyards in the world, with most viticulture in the state practiced between and feet above sea level. The mountain climate ensures warm summer days and cool nights. Colorado is home to two designated American Viticultural Areas of the Grand Valley AVA and the West Elks AVA, where most of the vineyards in the state are located. Approximately 100 commercial wineries operate in Colorado and about are planted to grapevines. Other wine regions include: the Four Corners area near Cortez, near Canyons of the Ancients National Monument, and Durango; Pikes Peak/Arkansas River Valley near Salida, Canon City, and Manitou Springs; and the Front Range between Fort Collins and Castle Rock, with many wineries located in the Denver metropolitan area.