The Swiss Confederation is a small landlocked alpine country in Central Europe with 7.7 million inhabitants (2009) and area of 41285 sq. km. It is organised as a federal republic of 26 cantons (states) and its capital is Bern. Other major cities are Zürich and Geneva, which are the two economic centres of Switzerland. The country has been settled for about 150000 years. The earliest advanced civilisations in Switzerland were the Hallstatt and La Tene cultures. In 15 BC the territory was integrated into the Roman Empire, and was settled in the 5th century by the Alemanni tribe. The first independent Swiss state was established at the end of the 13th century, when the rural communes of Uri, Schwyz, and Nidwalden formed an alliance. Over the centuries more and more cities and cantons joined the confederation. In the congress of Vienna in 1815 the European powers agreed to permanently recognise Swiss neutrality. Nowadays Switzerland is a technologically advanced country with a strong economy and one of the highest GDP in the world. The most important sectors of the Swiss economy are chemicals, health and pharmaceutical, measuring instruments, musical instruments, real estate, banking and insurance, tourism, and international organizations. Switzerland is not a member of the European Union. The official languages of Switzerland are German, French and Italian.