The territory of Azerbaijan is predominantly mountainous, there are three major mountain ranges that cross the country, towards the north, along the border with Russia are the mountains of the Greater Caucasus, where rises the highest mountain in the country, Mount Bazardüzü Dağı (4,485 metres), to the west, along the border with Armenia is the chain of the Lesser Caucasus, between the two mountainous systems extends the valley of the Kur River, the main river in the country, which flows in the Caspian Sea. Situated at the south of the country along the border with Iran are the Talysh Mountains. The economy of Azerbaijan is based on the mining and oil refining, thanks to rich deposits of oil and natural gas of the country. Important are also agriculture (rice, cereals, cotton, tobacco, fruits, tea, citrus fruits, corn) and breeding (cattle, sheep, silkworm).