The Russian Empire was a state that existed from 1721 until the Russian Revolution of 1917. It was the successor to the Tsardom of Russia, and the predecessor of the Soviet Union. It was the second largest contiguous empire the world had seen. At one point in 1866, it stretched from eastern Europe, across Asia, and into North America. At the beginning of the 19th century, Russia was the largest country in the world, extending from the Arctic Ocean to the north to the Black Sea on the south, from the Baltic Sea on the west to the Pacific Ocean on the east. Across this vast realm were scattered the Emperor's 176.4 million subjects, the largest population of the world at the time, who represented a great disparity in economic, ethnic, and religious positions. Also in 1913 Russia had a wealth of $257.7 billion the largest at the time, and the fourth largest in the history of modern empires. Its government, ruled by the Emperor, was one of the last absolute monarchies left in Europe. Prior to the outbreak of World War I in August of 1914 Russia was one of the five major Great Powers of Europe with an army of over 5 million men, the largest army in the world at the time.