Uzbekistan is located in the heart of Central Asia on the ancient Great Silk Road between Europe and Asia. The area had been conquered by the Turks, the armies of Alexander the Great, the Arabs, and the Mongols, before it was annexed by Russia in the late 19th century as part of the region then known as Turkestan. Uzbekistan became a republic within the Soviet Union in 1924, and gained independent in 1991 following the collapse of the Soviet Union. The country's political system is highly authoritarian, and the media is tightly controlled by the state. With a population of around 27.5 million, Uzbekistan is the most populous country in Central Asia. The country has a strong agricultural base and is one of the world’s largest producers of cotton. It is also endowed with abundant natural resources, including hydrocarbons, gold, copper, and uranium.