Since then, the EU grew with its first enlargement in 1973 when Ireland, Denmark and the United Kingdom joined the union and further enlargement in the following decades. The 1980s saw massive changes in Europe. Greece, Portugal and Spain joined during this period. The Single European Act was signed in 1986. This treaty was designed a six-year program and implemented to resolve remaining problems that are concerned with free trade across EU borders, thus forming the “Single Market”. However, the major event in that decade, which changed the face of Europe, was the fall of the Berlin. The borders between East and West Germany at the end of the 1980s were opened, leading to the reunification in 1990. With the end of communism across Europe, all the countries on the continent became closer neighbours. In 1993 the Single Market is completed with the ‘four freedoms’ of: movement of goods, services, people and money. During the 1990s, the EU also saw two further treaties which were the “Maastricht” Treaty on the European Union and the Treaty of Amsterdam to progress the European integration.