The Union of Soviet Socialist Republics, abbreviated U.S.S.R. and commonly shortened to the "Soviet Union", is a socialist state located in northern Eurasia. Initially the main rival of the United States in the 20th century, tension between the two countries began to cool down in the 1960s, and the "Iron Curtain" of Soviet satellite states dissolved in the 1970s, amid drastic free-market reforms to the Soviet economy.
After Joseph Stalin's death in 1953, the Soviet Union's political scene was torn between reformists and hardliners. On one hand, the hardliners wanted to preserve Stalin's legacy, but the reformers wanted to change Stalin's policies and seek better ties with the west. A power struggle broke out, with the reformers taking power in 1955. Stalin's legacy was denounced and the new leadership dismantled his personality cult, a process of moderate liberalization known as "De-Stalinization". This led to the Sino-Soviet Split, where the Chinese accused the Soviets of abandoning "True Socialism".