Berlin Wall was a deep anxiety over prospects for a reunified Germany. In September 1989, British Prime Minister Margaret Thatcher pleaded with Soviet President Mikhail Gorbachev not to let the Berlin Wall fall and confided that she wanted the Soviet leader to do what he could to stop it. After the fall of the Berlin Wall, French President François Mitterrand warned Thatcher that a unified Germany could make more ground than Adolf Hitler ever had and that Europe would have to bear the consequences. On 21 November 1989, Crosby, Stills & Nash performed the song "Chippin' Away" from Graham Nash's 1986 solo
Berlin Wall that year (). Similar, very limited arrangements were made in 1964, 1965 and 1966. In 1971, with the Four Power Agreement on Berlin, agreements were reached that allowed West Berliners to apply for visas to enter East Berlin and East Germany regularly, comparable to the regulations already in force for West Germans. However, East German authorities could still refuse entry permits. East Berliners and East Germans could not, at first, travel to West Berlin or West Germany at all. This regulation remained in force essentially until the fall of the Wall, but over the years several exceptions to these rules