The modern Republic of Azerbaijan lies along the northwest shore of the Caspian Sea, a historical point of contact between European and Eastern empires. Often conquered by foreign powers, what is now Azerbaijan was folded into the Russian Empire in 1813 as per the Treaty of Gulistan signed between the Russian Empire and Persia, and following a short period of independence in 1917-1920 upon the fall of the Russian Empire, became part of the USSR as the Azerbaijani Soviet Socialist Republic in the early 1920s. The late Soviet period saw a rise of localized violence in Azerbaijan, as in many parts of the USSR, leading to a war fought between Azerbaijan and Armenia over the former's separatist province of Nagorno-Karabakh. Tensions remain between the two countries following the emergence of both as independent states in 1991. Today, the largest country in the South Caucasus, Azerbaijan continues to hold a position between Turkey, Russia, and Iran, and its variegated peoples - including Azeris, Kurds, Jews, Russians, Armenians, Lezgians, and others - attest both to its modern growth and historical links from throughout the centuries. Azerbaijan's capital, Baku, was the site of the world's first commercial oil wells in the 1840s and the first oil-boom town by the 1880s. Today, the country's economy remains partially dependent upon oil exports, although state oil concerns share a bustling business environment in the capital with a marked and growing international banking and business community.