During the late–19th-century Scramble for Africa, Ethiopia and Liberia were the only two nations that preserved their sovereignty from long-term colonisation by a European colonial power, and many newly independent nations on the continent adopted its flag colours. During this period, Ethiopia established its modern borders through extensive conquest of territories to its east, west and south. Ethiopia was the first independent African member of the League of Nations and the United Nations. The country was occupied by Italy in 1936 and became Italian Ethiopia as part of Italian East Africa, until it was liberated during World War II. During Italian rule, the government abolished the centuries-old practice of slavery, and urbanization steadily increased. In 1974, the long-standing Ethiopian monarchy under Haile Selassie was overthrown by the Derg, a communist military government backed by the Soviet Union. In 1987, the Derg established the People's Democratic Republic of Ethiopia, which was overthrown in 1991 by the Ethiopian People's Revolutionary Democratic Front, who have been the ruling political coalition since.