On 11 March 1985 Mikhail Gorbachev became the new leader of the Soviet Union following the death of Konstantin Chernenko.

Later that year he met US president Ronald Reagan at the so-called fireside summit in Geneva. The talks were frank but friendly and the two sides pledged to make the world a safer place.

But there was deadlock over Mr Reagan's dream of a space-based Strategic Defence Initiative, popularly known as Star Wars.

Photo by Peter Marlow/Magnum Photos