The Cold War was a period of history featuring two global superpowers, capitalism and communism. It lasted roughly from the end of the Second World War to the collapse of the Berlin Wall in 1989. The main capitalist states were the USA and the Commonwealth. The main communist states were the USSR (United Soviet Socialists Republic) and China. The two superpowers feared and distrusted each other, but outright war was avoided. This was because so many nuclear warheads were built that human life would have been wiped out if they had been used. During this period intelligence organisations such as the CIA, SIS and KGB were formed, and vast changes were made to communications worldwide.