Central Asia is a region that extends from the Caspian Sea to western China. The northern border of Central Asia starts at Russia's southern border while its southern border is comprised of the Iranian, Afghan and Chinese national borders. Countries within Central Asia include Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan.
Over half of Central Asia is comprised of deserts, including the Karakum desert and Kyzylkum desert. Two main river systems, the Amu Darya and Syr Darya, work their way through the deserts. Both rivers drain into the Aral Sea, providing much of Central Asia's water resources. The climate in Central Asia is quite dry, leading to heavy reliance on the river systems for irrigation and agriculture.
Ethnically, Central Asia is populated by five large groups: Kazakh, Kyrgyz, Tajik, Turkmen and Uzbek. The primary religion in the area is Islam, with most adherents being Sunni. The economy of Central Asia is based on agriculture, mining and industry, with heavy emphasis on cotton due. Central Asia was completely under Russian rule by the 1870s, with the creation of five Soviet socialist republics in the 1920s and 1930s. After the collapse of the Soviet Union, the five Soviet socialist republics became the five independent countries that now occupy Central Asia.