Vienna (in German Wien) is the capital of the Republic of Austria and also one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.9 million. It is by far the largest city in Austria, as well as its cultural, economic, and politicalcentre. Settlements along the Danube near what is now the City of Vienna can be traced back to the 5th century B.C. These were of Celtic origin. The Romans established the garrison camp Vindobona in the 1st century AD. Remainders of the Roman camp can be seen at Hoher Markt. Vienna began its rise in importance in the Middle Ages when it was made the residence of the Babenbergs and the city walls were raised in 1200. Vienna would become the capital of the Habsburg Empire and remain so for almost seven centuries. Today its imperial past is still visible in monumental structures such as the Imperial Palace (Hofburg), the SchönbrunnPalace, the buildings along Ringstrasse, and many other sites throughout the city. The fall of the monarchy proved a turning point in Vienna's history. In 1922, the city was made a province in its own right. After the end of the Second World War and many years of Allied occupation, Austria regained its independence with the state treaty signed in 1955. Unperturbed by the nearby existing Iron Curtain, Vienna continued to build on its international role during the Cold War years. It became a UN seat.