Ukraine is a sovereign state in Eastern Europe, bordered by Russia to the east and northeast, Belarus to the northwest, Poland and Slovakia to the west, Hungary, Romania, and Moldova to the southwest, and the Black Sea and Sea of Azov to the south and southeast, respectively. It is the largest wholly European country and the second largest country in Europe, after the European part of the Russian Federation. Ukraine has a mostly temperate climate, with the exception of the southern coast of Crimea which has a subtropical climate. Ukraine has long been a global breadbasket because of its extensive, fertile farmlands and is one of the world's largest grain exporters. The landscape of Ukraine consists mostly of fertile plains (or steppes) and plateaus, crossed by rivers as they flow south into the Black Sea and the smaller Sea of Azov. Significant natural resources in Ukraine include iron ore, coal, manganese, natural gas, oil, salt, sulphur, graphite, titanium, magnesium, kaolin, nickel, mercury, timber and an abundance of arable land. Despite this, the country faces a number of major environmental issues such as inadequate supplies of potable water; air and water pollution and deforestation, as well as radiation contamination in the north-east from the 1986 accident at the Chernobyl Nuclear Power Plant.