The Wall fell as the combined result of both internal and external pressures. The evolution of the USSR played a crucial role in this process.
On his first official visit to West Germany in May1989, MikhalGorbachev, whose ambition was to save his country from decline and ruin through an innovative policy based on restructuring ( perestroka ) and openness ( glasnost ), informed Chancellor Kohl that the Brezhnev doctrine had been abandoned; Moscow was no longer willing to use force to prevent democratic transformation of its satellite states.
This was the kiss of death for East Germany because there was no need to have two separate Germanys if the Soviets and US were no longer going to be involved in the Cold War
Finally on July 1, 1990, East and West Germany were united. They assumed West Germany's old name, The Federal Republic of Germany.