1991
Break up of the Soviet Union in 1991. On December 8, 1991, the presidents of Russia, Ukraine and Belarus signed the Belavezha Accords which declared the Soviet Union dissolved and established the Commonwealth of Independent States (CIS), in its place. On December 25, 1991 the Soviet Union is officially dissolved, effectively ending the Cold War. United States becomes sole world superpower.
From 1945 until dissolution in 1991(a period known as the Cold War) the Soviet Union and the United States of America were the two world superpowers that dominated the global agenda of economic policy, foreign affairs, military operations, cultural exchange, scientific advancements including the pioneering of space exploration, and sports (including the Olympic Games and various world championships).