Georgia is a country located in the Caucasus region of Eurasia. It is bordered by the Black Sea, Russia, Turkey, Armenia, and Azerbaijan. The capital city is Tbilisi. The Kingdom of Georgia experienced a Golden Age under the rule of King David IV and Queen Tamar in the twelfth and early thirteenth centuries. After the Golden Age, the kingdom eventually disintegrated and was ruled by various powers, including the Mongols and the Ottoman Empire. In the eighteenth century, the eastern Georgia Kingdom of Kartli-Kakheti forged an alliance with the Russian Empire. Following the Russian Revolution and Civil War in 1917, Georgia eventually emerged as an independent republic before the Red Army invasion in 1921, and it became a founding member of the Soviet Union. Georgia seceded from the Soviet Union in 1991. Its strained relationship with Russia includes the brief Russo-Georgia War in 2008 and ongoing territorial disputes.