Ukraine, country located in eastern Europe, the second largest on the continent after Russia. The capital is Kyiv, located on the Dnieper River in north-central Ukraine. A fully independent Ukraine emerged only late in the 20th century, after long periods of successive domination by Poland-Lithuania, Russia, and the Union of Soviet Socialist Republics (U.S.S.R.). Ukraine had experienced a brief period of independence in 1918–20, but portions of western Ukraine were ruled by Poland, Romania, and Czechoslovakia in the period between the two World Wars, and Ukraine thereafter became part of the Soviet Union as the Ukrainian Soviet Socialist Republic (S.S.R.). When the Soviet Union began to unravel in 1990–91, the legislature of the Ukrainian S.S.R. declared sovereignty (July 16, 1990) and then outright independence (August 24, 1991), a move that was confirmed by popular approval in a plebiscite (December 1, 1991). With the dissolution of the U.S.S.R. in December 1991, Ukraine gained full independence. The country changed its official name to Ukraine, and it helped to found the Commonwealth of Independent States (CIS), an association of countries that were formerly republics of the Soviet Union.
Ukraine is a developing country and ranks 88th on the Human Development Index. At US$40, it has the lowest median wealth per adult in the world, and suffers from a very high poverty rate as well as severe corruption. However, because of its extensive fertile farmlands, Ukraine is one of the world's largest grain exporters. It also maintains the second-largest military in Europe after that of Russia. Ukraine is a unitary republic under a semi-presidential system with separate powers: legislative, executive and judicial branches. The country is a member of the United Nations, the Council of Europe, the Organization for Security and Co-operation in Europe (OSCE), the GUAM organization, and one of the founding states of the Commonwealth of Independent States.