In 1990 East and West Germany reunified. What event had the greatest impact on the reunification of Germany?

The fall of the Berlin Wall on November 9, 1989, had the greatest impact on the reunification of Germany. This monumental event symbolized the collapse of Communist control in Eastern Europe and allowed East Germans to freely cross into West Germany, igniting public support for reunification. The subsequent political changes and negotiations between East and West Germany, along with broader movements in Europe, led to the formal reunification on October 3, 1990.