Central Asia stretches from the Caspian Sea in the west to China in the east and from Afghanistan in the south to Russia in the north. its population is 69,787,760; 17.43/km2 (45.1/sq mi). central Asia is sometimes referred to as Turkestan. Central Asia has a population of about 70 million, consisting of five republics: Kazakhstan (pop. 18 million), Kyrgyzstan (6 million), Tajikistan (9 million), Turkmenistan (6 million), and Uzbekistan (31 million). Afghanistan (pop. central Asia is most notable for being home to the 'stans': Rugged countries with limited arable land, historically coveted for their position between Europe and East Asia, rather than for their resources (although petroleum and natural gas reserves in the region are becoming more and more important).