Azerbaijan is rich in mineral and climatic resources. The Caspian Sea oil & gas reserves are some of the world's largest deposits. Azerbaijan has also substantial explored deposits of precious metals (including gold and silver), ferrous and non-ferrous metals, various construction raw materials and so on. One of the major resources of the country is its natural diversity. Despite its relatively small size, Azerbaijan has a number of distinct climatic zones ranging from humid subtropical to semi-arctic due to its complex terrain and geography. This creates unique opportunities in agriculture and tourism.