Lithuania is a country in northeastern Europe. It borders on Latvia, Belarus, Poland and the Russian exclave of the Kaliningrad Oblast. Lithuania has been a member of the United Nations Organization since 1991. The country joined the World Trade Organization in 2001, it became member of the European Union and NATO in 2004. According to one of the researches, the geographical centre of Europe is situated in Lithuania, in Bernotai, or Purnuškės, near Vilnius.