Ukraine, with its area of 603,628 km2, is the second largest country in Eastern Europe. It is bordered by the Russian Federation to the east and northeast, Belarus to the northwest, Poland, Slovakia and Hungary to the west, Romania and Moldova to the southwest, and the Black Sea and Sea of Azov to the south and southeast respectively.
Ukraine's modern history began with the East Slavs. From at least the 9th century, Ukraine was the center of the medieval living area of the East Slavs. This state, known as Kievan Rus', became a large and powerful nation, but disintegrated in the 12th century. After the Great Northern War, Ukraine was divided among a number of regional powers, and by the 19th century, the largest part of Ukraine was integrated into the Russian Empire, with the rest under Austro-Hungarian control.
After a chaotic period of incessant warfare and several attempts at independence (1917–21) following World War I and the Russian Civil War, emerged on December 30, 1922 as one of the founding republics of the Soviet Union. The Ukrainian Soviet Socialist Republic's territory was enlarged westward shortly before and after World War II, and southwards in 1954 with the Crimea transfer. In 1945, the Ukrainian SSR became one of the co-founding members of the United Nations.
Ukraine became independent again after the dissolution of the Soviet Union in 1991. Herewith began a period of transition to a market economy, in which Ukraine was stricken with an eight year recession. Since then though, the economy experienced a high increase in GDP growth. Ukraine was caught up in the worldwide economic crisis in 2008 and the economy plunged. GDP fell 20% from spring 2008 to spring 2009, then leveled off as analysts compared the magnitude of the downturn to the worst years of economic depression during the early 1990s.
Ukraine is a unitary state composed of 24 oblasts (provinces), one autonomous republic (Crimea), and two cities with special status: Kyiv, its capital and largest city, and Sevastopol, which houses the Russian Black Sea Fleet under a leasing agreement. Ukraine is a republic under a semi-presidential system with separate legislative, executive, and judicial branches.