Spanning 11 time zones, Russia is the largest country on earth in terms of surface area, although large tracts in the north and east are inhospitable and sparsely populated. In 1547, Ivan IV (the Terrible) was crowned czar of Russia, beginning a tradition of czarist rule and expansionism. Czarist rule continued until the 1917 Russian Revolution that overthrew the imperial household and the Communists, under Vladimir Lenin, seized power. Civil war broke out in 1918 between the Red Army and White Russians, or anti-communists, and lasted until 1920 when the Bolsheviks triumphed. After the Red army conquered Ukraine, Belarus, Azerbaijan, Georgia, and Armenia, a new nation, the Union of Soviet Socialist Republics (U.S.S.R.), was formed in 1922. The brutal rule of Josef Stalin (1928-53) strengthened Communist rule, and in the 1930s the country saw the forced collectivization of tens of millions of its citizens in state agricultural and industrial enterprises. Millions died in the process, and millions more died in political purges. The Soviet Union emerged from World War II with extended influence, occupying many Eastern European nations. Mikhail Gorbachev took office in 1985 and introduced openness and a restructuring of the government. The new political climate resulted in the ultimate breakup of the Soviet Union, and by late 1991 Russia and 14 other former Soviet republics emerged as independent states. Russia is endowed with vast natural resources, including oil, natural gas, coal, and timber. It holds the world's largest natural gas reserves, the second largest coal reserves, and the eighth largest oil reserves. Russia is also the world's largest exporter of natural gas, and the second largest oil exporter.