Slovakia is a landlocked country in Central Europe, formally known as the Slovak Republic. It is bordered on the north by Poland, on the east by Ukraine, on the south by Hungary, on the west by Austria, and on the northwest by the Czech Republic. Slovakia covers about 49,000 square kilometers and has a population of over 5.4 million people. Bratislava is the capital and largest city, while Koice is the second largest. The Slavs first arrived in what is now Slovakia in the 5th and 6th centuries. They were instrumental in the establishment of Samo's Empire in the 7th century. They established the Principality of Nitra in the 9th century, which was later annexed by the Principality of Moravia to form Great Moravia. Following the fall of Great Moravia in the 10th century, the region was absorbed into the Principality of Hungary, which would later become the Kingdom of Hungary in 1000. Following the Mongol invasion of Europe in 1241 and 1242, most of the region was lost. After World War I, and the breakup of Austria-Hungary, the region was largely recovered thanks to Béla IV of Hungary, who also settled Germans, leading them to become an significant ethnic group in the area, especially in what are now parts of central and eastern Slovakia. During World War II, the Slovak Republic existed as a partly recognised client state of Nazi Germany. Czechoslovakia was re-established as an independent nation at the end of World War II. Czechoslovakia was an independent country that became part of the Soviet-led Eastern Bloc after a coup in 1948. The Prague Spring culminated attempts to liberalize communism in Czechoslovakia, which were crushed by the Warsaw Pact invasion of Czechoslovakia in August 1968. The Velvet Revolution ended Communist rule in Czechoslovakia peacefully in 1989. After the peaceful division of Czechoslovakia, recognized as the Velvet Divorce, Slovakia became an independent state on January 1, 1993. Slovakia is a developing nation with a high-income economy that scores extremely well on the Human Development Index. It also scores well on civil rights, press freedom, internet freedom, democratic governance, and peacefulness measures. The country combines a market economy with a robust social insurance system, offering residents universal health care, free education, and one of the OECD's longest paid parental leave periods. Slovakia is a member of the European Union, the Eurozone, NATO, the United Nations, the OECD, the World Trade Organization, CERN, the OSCE, the Council of Europe, and the Visegrád Group. With 1.1 million cars produced in 2019, it is the world's largest per-capita car manufacturer, accounting for 43% of its overall manufacturing production.