the ministries of Culture, Defence, Education, Finance, Foreign Affairs, Health, Infrastructure, Internal Affairs, Justice and Tourism are spread over Tirana. The city is also the home to all the consulates and embassies in Albania, thereby making it an important centre for international diplomacy in the country. International relations Tirana is a founding member of the Union of Albanian Municipalities in the Region. Tirana is twinned with Ankara, Beijing, Bursa, Doha, Florence, Kharkiv, Sarajevo and has signed partnership agreements with Verona and Zagreb. It has also signed special bilateral agreements with Zaragoza. Economy Tirana is the heart of the economy of Albania and the most industrialised and economically fastest growing region in Albania. Of the main sectors, the tertiary sector is the most important for the economy of Tirana and employs more than 68% of work force of Tirana. 26% of the working population makes up the secondary sector followed by the primary sector with only 5%. The city began to develop at the beginning of the 16th century as it was part of the Ottoman Empire, when a bazaar was established, and its craftsmen manufactured silk and cotton fabrics, leather, ceramics and iron, silver and gold artefacts. In the 20th century, the city and its surrounding areas expanded rapidly and became the most heavily industrialised region of the country. The most significant contribution is made by the tertiary sector which has developed considerably since the fall of communism in Albania. Forming the financial centre of the country, the financial industry is a major component of the city's tertiary sector and remains in good conditions overall due to privatization and the commendable monetary policy. All of the most important financial institutions, such as the Bank of Albania and the Albanian Stock Exchange are centred in Tirana as well as most of the banking companies such as the Banka Kombëtare Tregtare, Raiffeisen Bank, Credins Bank, Intesa Sanpaolo Bank and Tirana Bank. The telecommunication industry represents another major and growing contributor to the sector. A rapid development occurred as well as after the end of communism and decades of isolationism mainly due to the new national policy of reform and opening up sped up the industry's development. Vodafone, Telekom Albania and Eagle are the leading telecommunication providers in Tirana, as in all the country. The tourism industry of the city has expanded in recent years to become a vital component of the economy.