The Balkans, a region in southeastern Europe, have a complex history marked by shifting empires, diverse ethnic groups, and numerous conflicts. The Kingdom of Serbs, Croats, and Slovenes, formed after World War I, later became Yugoslavia, a country encompassing various South Slavic peoples. Yugoslavia experienced periods of unity and division, including World War II and the collapse of the Socialist Federal Republic of Yugoslavia in the 1990s, leading to the formation of several independent nations.