The Azerbaijan Soviet Socialist Republic was a constituent republic of the Soviet Union from 1920 until 1991. It was established after the Bolshevik Revolution and was part of the larger Transcaucasian Soviet Federative Socialist Republic before becoming a separate entity. The capital city was Baku, known for its oil production and strategic location along the Caspian Sea. During its existence, the republic underwent significant industrialization and urbanization, influenced by Soviet policies. The economy was centrally planned, focusing on heavy industry and agriculture. In 1991, Azerbaijan declared independence following the dissolution of the Soviet Union, marking the end of its status as a Soviet republic.