Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south. Poland borders Kaliningrad Oblast and Lithuania to the north; Belarus and Ukraine to the east; Slovakia and the Czech Republic to the south; and Germany to the west. The territory has a varied landscape, diverse ecosystems, and a temperate climate. Poland is composed of sixteen voivodeships and is the fifth most populous member state of the European Union (EU), with over 38 million people, and the fifth largest EU country by land area, covering 312,696 km2 (120,733 sq mi). The capital and largest city is Warsaw; other major cities include Kraków, Wrocław, Łódź, Poznań, and Gdańsk. Prehistoric human activity on Polish soil dates to the Lower Paleolithic, with continuous settlement since the end of the Last Glacial Period. Culturally diverse throughout late antiquity, in the early medieval period the region became inhabited by the West Slavic tribal Polans, who gave Poland its name. The process of establishing statehood coincided with the conversion of a pagan ruler of the Polans to Christianity in 966 under the auspices of the Roman Catholic Church. The Kingdom of Poland emerged in 1025, and in 1569 cemented its long-standing association with Lithuania, thus forming the Polish–Lithuanian Commonwealth.