Located in the Caucasus region, Azerbaijan is a former Soviet republic that gained its independence in 1991, and has been flourishing ever since the 19th century due to an unprecedented oil boom. The country borders Russia to the north, the Caspian Sea to the east, Georgia to the northwest, Armenia to the west, and Iran to the south. Azerbaijan's capital is Baku, which is also the largest city and port in the country, and its population is around 8.8 million (2009).