Kaliningrad Oblast is a federal subject of Russia (an oblast) situated on the Baltic coast. It has a population of 941,500 (2010 Census preliminary results). The oblast forms the westernmost part of the Russian Federation, but it has no land connection to the rest of Russia. Since its creation it has been an exclave of the Russian SFSR and then the Russian Federation. The fall of the Soviet Union left it isolated from the 'mainland'. It is surrounded by Lithuania, Poland, and the Baltic Sea. Borderless travel to the main part of Russia is only possible by sea and/or air. This political isolation became more pronounced when Lithuania and Poland both became members of the European Union and NATO, and entered the Schengen Zone, which means that the oblast is surrounded by the territories of these organizations as well. The oblast's largest city and the administrative center is Kaliningrad, which has historical significance as both a major city of the historical state of Prussia and the capital of the former German province of East Prussia, partitioned after World War II between the USSR and Poland, and renamed after the Soviet Head of State Mikhail Kalinin.