Passers-by look at painted dominos symbolizing pieces of the Berlin Wall at the Brandenburg Gate in Berlin, Germany, 08 November 2009. Some 1,000 of these dominos have been set up between the Reichstag building, Brandenburg Gate and Potsdam Square and mar
Bulgaria's Prime Minister Boyko Borissov will join world leaders and thousands of people in Berlin to mark 20 years since the Berlin Wall's fall, an event that paved the way for the end of the Cold War.
Borisov will also attend the formal reception commemorating the event hosted by German President Horst Koehler.
The main celebrations in the city will be at the Brandenburg Gate - the symbol of German reunification in 1990. Giant dominoes will be toppled to show how Communist governments in Eastern Europe fell one after another in 1989.
Communist East Germany erected the 155km (96-mile) concrete Wall in 1961 to encircle West Berlin. It was put up to prevent East Germans from fleeing into the capitalist enclave.
More than 100 people are believed to have been killed at the Wall while trying to escape.
The barrier was unexpectedly opened on 9 November 1989, following weeks of pro-democracy protests.
German Chancellor Angela Merkel, who grew up in East Germany, will lead the celebrations on Monday.
Last week, she said the fall of the Wall was "the happiest day in recent German history".
Among those invited are French President Nicolas Sarkozy, British Prime Minister Gordon Brown and US Secretary of State Hillary Clinton.
They also will be joined by Former Polish President Lech Walesa, who led the Solidarity free-trade union against the Communist regime, Former Hungarian Prime Minister Miklos Nemeth, whose decision to open his country's borders first allowed East Germans to flee to the West, Former Soviet leader Mikhail Gorbachev, who let the nations of Eastern Europe go their own way.