More than 30 past and present world leaders are in the German capital to mark 20 years since the collapse of the Berlin Wall. The event paved the way for the country’s reunification, the end of the Cold War and the break-up of the Soviet Union.Today’s commemorative events began with a special service in which pivotal figures from the era that ushered in the collapse of communism in eastern Europe took part . Among them are former US chief diplomat Henry Kissinger and ex-Soviet leader Mikhail Gorbachev. Joining them will be the leaders of the nations which occupied postwar Germany, apart from the United States, which will be represented by Secretary of State Hillary Clinton. German Chancellor, Angela Merkel, who was working as a scientific researcher in East Berlin at the time, described the the fall of the Wall as “the happiest day in recent Germany history”.